* [Patch v8 01/12] perf/x86: Remove redundant is_x86_event() prototype
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss Dapeng Mi
` (10 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
2 is_x86_event() prototypes are defined in perf_event.h. Remove the
redundant one.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/perf_event.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 2b969386dcdd..285779c73479 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -1124,7 +1124,6 @@ static struct perf_pmu_format_hybrid_attr format_attr_hybrid_##_name = {\
.pmu_type = _pmu, \
}
-int is_x86_event(struct perf_event *event);
struct pmu *x86_get_pmu(unsigned int cpu);
extern struct x86_pmu x86_pmu __read_mostly;
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
2025-10-15 6:44 ` [Patch v8 01/12] perf/x86: Remove redundant is_x86_event() prototype Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-22 8:12 ` Mi, Dapeng
2025-10-15 6:44 ` [Patch v8 03/12] perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call Dapeng Mi
` (9 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi,
kernel test robot, Kan Liang
When intel_pmu_drain_pebs_icl() is called to drain PEBS records, the
perf_event_overflow() could be called to process the last PEBS record.
While perf_event_overflow() could trigger the interrupt throttle and
stop all events of the group, like what the below call-chain shows.
perf_event_overflow()
-> __perf_event_overflow()
->__perf_event_account_interrupt()
-> perf_event_throttle_group()
-> perf_event_throttle()
-> event->pmu->stop()
-> x86_pmu_stop()
The side effect of stopping the events is that all corresponding event
pointers in cpuc->events[] array are cleared to NULL.
Assume there are two PEBS events (event a and event b) in a group. When
intel_pmu_drain_pebs_icl() calls perf_event_overflow() to process the
last PEBS record of PEBS event a, interrupt throttle is triggered and
all pointers of event a and event b are cleared to NULL. Then
intel_pmu_drain_pebs_icl() tries to process the last PEBS record of
event b and encounters NULL pointer access.
To avoid this NULL event access and potential PEBS record loss, snapshot
cpuc->events[] into a local events[] before drian_pebs() helper calling
perf_event_overflow() and then use the local events[] to process the
left PEBS records.
Besides intel_pmu_drain_pebs_nhm() has similar issue and fix it as well.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202507042103.a15d2923-lkp@intel.com
Fixes: 9734e25fbf5a ("perf: Fix the throttle logic for a group")
Suggested-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/ds.c | 36 +++++++++++++++++++++++++++++++-----
1 file changed, 31 insertions(+), 5 deletions(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index c0b7ac1c7594..259a0ff807eb 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2487,6 +2487,7 @@ static void intel_pmu_pebs_event_update_no_drain(struct cpu_hw_events *cpuc, u64
static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_data *data)
{
+ struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct debug_store *ds = cpuc->ds;
struct perf_event *event;
@@ -2526,9 +2527,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
/* PEBS v3 has more accurate status bits */
if (x86_pmu.intel_cap.pebs_format >= 3) {
- for_each_set_bit(bit, (unsigned long *)&pebs_status, size)
+ for_each_set_bit(bit, (unsigned long *)&pebs_status, size) {
counts[bit]++;
-
+ if (counts[bit] && !events[bit])
+ events[bit] = cpuc->events[bit];
+ }
continue;
}
@@ -2566,19 +2569,31 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
* If collision happened, the record will be dropped.
*/
if (pebs_status != (1ULL << bit)) {
- for_each_set_bit(i, (unsigned long *)&pebs_status, size)
+ for_each_set_bit(i, (unsigned long *)&pebs_status, size) {
error[i]++;
+ if (error[i] && !events[i])
+ events[i] = cpuc->events[i];
+ }
continue;
}
counts[bit]++;
+ /*
+ * perf_event_overflow() called by below __intel_pmu_pebs_events()
+ * could trigger interrupt throttle and clear all event pointers of
+ * the group in cpuc->events[] to NULL. So snapshot the event[] before
+ * it could be cleared. This avoids the possible NULL event pointer
+ * access and PEBS record loss.
+ */
+ if (counts[bit] && !events[bit])
+ events[bit] = cpuc->events[bit];
}
for_each_set_bit(bit, (unsigned long *)&mask, size) {
if ((counts[bit] == 0) && (error[bit] == 0))
continue;
- event = cpuc->events[bit];
+ event = events[bit];
if (WARN_ON_ONCE(!event))
continue;
@@ -2603,6 +2618,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_data *data)
{
+ struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
short counts[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {};
void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -2655,6 +2671,16 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
setup_pebs_adaptive_sample_data);
}
last[bit] = at;
+
+ /*
+ * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
+ * could trigger interrupt throttle and clear all event pointers of
+ * the group in cpuc->events[] to NULL. So snapshot the event[] before
+ * it could be cleared. This avoids the possible NULL event pointer
+ * access and PEBS record loss.
+ */
+ if (counts[bit] && !events[bit])
+ events[bit] = cpuc->events[bit];
}
}
@@ -2662,7 +2688,7 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
if (!counts[bit])
continue;
- event = cpuc->events[bit];
+ event = events[bit];
__intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
counts[bit], setup_pebs_adaptive_sample_data);
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss
2025-10-15 6:44 ` [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss Dapeng Mi
@ 2025-10-22 8:12 ` Mi, Dapeng
2025-10-22 11:24 ` Peter Zijlstra
0 siblings, 1 reply; 22+ messages in thread
From: Mi, Dapeng @ 2025-10-22 8:12 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, kernel test robot,
Kan Liang
On 10/15/2025 2:44 PM, Dapeng Mi wrote:
> When intel_pmu_drain_pebs_icl() is called to drain PEBS records, the
> perf_event_overflow() could be called to process the last PEBS record.
>
> While perf_event_overflow() could trigger the interrupt throttle and
> stop all events of the group, like what the below call-chain shows.
>
> perf_event_overflow()
> -> __perf_event_overflow()
> ->__perf_event_account_interrupt()
> -> perf_event_throttle_group()
> -> perf_event_throttle()
> -> event->pmu->stop()
> -> x86_pmu_stop()
>
> The side effect of stopping the events is that all corresponding event
> pointers in cpuc->events[] array are cleared to NULL.
>
> Assume there are two PEBS events (event a and event b) in a group. When
> intel_pmu_drain_pebs_icl() calls perf_event_overflow() to process the
> last PEBS record of PEBS event a, interrupt throttle is triggered and
> all pointers of event a and event b are cleared to NULL. Then
> intel_pmu_drain_pebs_icl() tries to process the last PEBS record of
> event b and encounters NULL pointer access.
>
> To avoid this NULL event access and potential PEBS record loss, snapshot
> cpuc->events[] into a local events[] before drian_pebs() helper calling
> perf_event_overflow() and then use the local events[] to process the
> left PEBS records.
>
> Besides intel_pmu_drain_pebs_nhm() has similar issue and fix it as well.
>
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Closes: https://lore.kernel.org/oe-lkp/202507042103.a15d2923-lkp@intel.com
> Fixes: 9734e25fbf5a ("perf: Fix the throttle logic for a group")
> Suggested-by: Kan Liang <kan.liang@linux.intel.com>
> Tested-by: kernel test robot <oliver.sang@intel.com>
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
> arch/x86/events/intel/ds.c | 36 +++++++++++++++++++++++++++++++-----
> 1 file changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index c0b7ac1c7594..259a0ff807eb 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -2487,6 +2487,7 @@ static void intel_pmu_pebs_event_update_no_drain(struct cpu_hw_events *cpuc, u64
>
> static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_data *data)
> {
> + struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
> struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> struct debug_store *ds = cpuc->ds;
> struct perf_event *event;
> @@ -2526,9 +2527,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
>
> /* PEBS v3 has more accurate status bits */
> if (x86_pmu.intel_cap.pebs_format >= 3) {
> - for_each_set_bit(bit, (unsigned long *)&pebs_status, size)
> + for_each_set_bit(bit, (unsigned long *)&pebs_status, size) {
> counts[bit]++;
> -
> + if (counts[bit] && !events[bit])
> + events[bit] = cpuc->events[bit];
> + }
> continue;
> }
>
> @@ -2566,19 +2569,31 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
> * If collision happened, the record will be dropped.
> */
> if (pebs_status != (1ULL << bit)) {
> - for_each_set_bit(i, (unsigned long *)&pebs_status, size)
> + for_each_set_bit(i, (unsigned long *)&pebs_status, size) {
> error[i]++;
> + if (error[i] && !events[i])
> + events[i] = cpuc->events[i];
> + }
> continue;
> }
>
> counts[bit]++;
> + /*
> + * perf_event_overflow() called by below __intel_pmu_pebs_events()
> + * could trigger interrupt throttle and clear all event pointers of
> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
> + * it could be cleared. This avoids the possible NULL event pointer
> + * access and PEBS record loss.
> + */
> + if (counts[bit] && !events[bit])
> + events[bit] = cpuc->events[bit];
> }
>
> for_each_set_bit(bit, (unsigned long *)&mask, size) {
> if ((counts[bit] == 0) && (error[bit] == 0))
> continue;
>
> - event = cpuc->events[bit];
> + event = events[bit];
> if (WARN_ON_ONCE(!event))
> continue;
>
> @@ -2603,6 +2618,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
>
> static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_data *data)
> {
> + struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
> short counts[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {};
> void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
> struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> @@ -2655,6 +2671,16 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
> setup_pebs_adaptive_sample_data);
> }
> last[bit] = at;
> +
> + /*
> + * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
> + * could trigger interrupt throttle and clear all event pointers of
> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
> + * it could be cleared. This avoids the possible NULL event pointer
> + * access and PEBS record loss.
> + */
> + if (counts[bit] && !events[bit])
> + events[bit] = cpuc->events[bit];
> }
> }
>
> @@ -2662,7 +2688,7 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
> if (!counts[bit])
> continue;
>
> - event = cpuc->events[bit];
> + event = events[bit];
>
> __intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
> counts[bit], setup_pebs_adaptive_sample_data);
Hi Peter,
Just think twice about this fix, it seems current fix is incomplete.
Besides the PEBS handler, the basic PMI handler could encounter same issue,
like the below code in handle_pmi_common(),
for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
struct perf_event *event = cpuc->events[bit];
u64 last_period;
handled++;
if (!test_bit(bit, cpuc->active_mask))
continue;
Although the NULL event would not be accessed by checking
the cpuc->active_mask, the potential overflow process of these NULL events
is skipped as well, it may cause data loss.
Moreover, current approach defines temporary variables to snapshot the
active events, the temporary variables may consume too much stack memory
(384 bytes).
So I enhance the fix as below. Do you have any comment on this? Thanks.
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 745caa6c15a3..7dc82ca87c11 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1738,6 +1738,25 @@ int x86_pmu_handle_irq(struct pt_regs *regs)
return handled;
}
+inline void x86_pmu_snapshot_overflow_events(struct cpu_hw_events *cpuc)
+{
+ /*
+ * The perf_event_overflow() could call perf_event_throttle_group()
+ * to throttle all the events of group and clear all the corresponding
+ * cpuc->events[] pointers in PMI handler. This leads to PMI handler
+ * could get a NULL event pointer from cpuc->events[] when trying to
+ * process the overflow of the group member events. Even PMI handler
+ * checks if the event is NULL before acessing it and won't trigger
+ * a page fault, but PMI handler has to skip to overflow processing of
+ * these group member events and leads to data loss.
+ *
+ * To avoid this issue, snapshot the active events. Please notice this
+ * function should be called before the perf_event_overflow() calling
+ * loop in PMI handler. See handle_pmi_common().
+ */
+ memcpy(cpuc->overflow_events, cpuc->events, sizeof(cpuc->events));
+}
+
void perf_events_lapic_init(void)
{
if (!x86_pmu.apic || !x86_pmu_initialized())
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 28f5468a6ea3..1d86600e3e6d 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3241,13 +3241,14 @@ static int handle_pmi_common(struct pt_regs *regs,
u64 status)
*/
status |= cpuc->intel_cp_status;
+ x86_pmu_snapshot_overflow_events(cpuc);
for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
- struct perf_event *event = cpuc->events[bit];
+ struct perf_event *event = cpuc->overflow_events[bit];
u64 last_period;
handled++;
- if (!test_bit(bit, cpuc->active_mask))
+ if (WARN_ON_ONCE(!event))
continue;
/*
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index c0b7ac1c7594..45b5be3643d4 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2574,11 +2574,13 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
*iregs, struct perf_sample_d
counts[bit]++;
}
+ x86_pmu_snapshot_overflow_events(cpuc);
+
for_each_set_bit(bit, (unsigned long *)&mask, size) {
if ((counts[bit] == 0) && (error[bit] == 0))
continue;
- event = cpuc->events[bit];
+ event = cpuc->overflow_events[bit];
if (WARN_ON_ONCE(!event))
continue;
@@ -2634,6 +2636,8 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs
*iregs, struct perf_sample_d
if (!iregs)
iregs = &dummy_iregs;
+ x86_pmu_snapshot_overflow_events(cpuc);
+
/* Process all but the last event for each counter. */
for (at = base; at < top; at += basic->format_size) {
u64 pebs_status;
@@ -2644,7 +2648,7 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs
*iregs, struct perf_sample_d
pebs_status = basic->applicable_counters &
cpuc->pebs_enabled & mask;
for_each_set_bit(bit, (unsigned long *)&pebs_status,
X86_PMC_IDX_MAX) {
- event = cpuc->events[bit];
+ event = cpuc->overflow_events[bit];
if (WARN_ON_ONCE(!event) ||
WARN_ON_ONCE(!event->attr.precise_ip))
@@ -2662,7 +2666,9 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs
*iregs, struct perf_sample_d
if (!counts[bit])
continue;
- event = cpuc->events[bit];
+ event = cpuc->overflow_events[bit];
+ if (WARN_ON_ONCE(!event))
+ continue;
__intel_pmu_pebs_last_event(event, iregs, regs, data,
last[bit],
counts[bit],
setup_pebs_adaptive_sample_data);
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 285779c73479..32c6c3377621 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -256,6 +256,7 @@ struct cpu_hw_events {
* Generic x86 PMC bits
*/
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter
order */
+ struct perf_event *overflow_events[X86_PMC_IDX_MAX]; /* in
counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
unsigned long dirty[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
int enabled;
@@ -1277,6 +1278,8 @@ void x86_pmu_enable_event(struct perf_event *event);
int x86_pmu_handle_irq(struct pt_regs *regs);
+void x86_pmu_snapshot_overflow_events(struct cpu_hw_events *cpuc);
+
void x86_pmu_show_pmu_cap(struct pmu *pmu);
static inline int x86_pmu_num_counters(struct pmu *pmu)
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss
2025-10-22 8:12 ` Mi, Dapeng
@ 2025-10-22 11:24 ` Peter Zijlstra
2025-10-23 2:29 ` Mi, Dapeng
0 siblings, 1 reply; 22+ messages in thread
From: Peter Zijlstra @ 2025-10-22 11:24 UTC (permalink / raw)
To: Mi, Dapeng
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, kernel test robot,
Kan Liang
On Wed, Oct 22, 2025 at 04:12:14PM +0800, Mi, Dapeng wrote:
> Just think twice about this fix, it seems current fix is incomplete.
> Besides the PEBS handler, the basic PMI handler could encounter same issue,
> like the below code in handle_pmi_common(),
>
> for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
> struct perf_event *event = cpuc->events[bit];
> u64 last_period;
>
> handled++;
>
> if (!test_bit(bit, cpuc->active_mask))
> continue;
>
> Although the NULL event would not be accessed by checking
> the cpuc->active_mask, the potential overflow process of these NULL events
> is skipped as well, it may cause data loss.
>
> Moreover, current approach defines temporary variables to snapshot the
> active events, the temporary variables may consume too much stack memory
> (384 bytes).
>
> So I enhance the fix as below. Do you have any comment on this? Thanks.
So I didn't like the previous and I like this even less. What about
something like this instead?
I quickly went through the cpuc->event[ users and they all either check
active_mask or, in case of the PEBS stuff, check pebs_enabled mask
(which should be a subset of active_mask).
(the PEBS last case depends on count being 0 for all counters that are
not set in pebs_enabled)
WDYT?
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 745caa6c15a3..74479f9d6eed 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1344,6 +1344,7 @@ static void x86_pmu_enable(struct pmu *pmu)
hwc->state |= PERF_HES_ARCH;
x86_pmu_stop(event, PERF_EF_UPDATE);
+ cpuc->events[hwc->idx] = NULL;
}
/*
@@ -1365,6 +1366,7 @@ static void x86_pmu_enable(struct pmu *pmu)
* if cpuc->enabled = 0, then no wrmsr as
* per x86_pmu_enable_event()
*/
+ cpuc->events[hwc->idx] = event;
x86_pmu_start(event, PERF_EF_RELOAD);
}
cpuc->n_added = 0;
@@ -1531,7 +1533,6 @@ static void x86_pmu_start(struct perf_event *event, int flags)
event->hw.state = 0;
- cpuc->events[idx] = event;
__set_bit(idx, cpuc->active_mask);
static_call(x86_pmu_enable)(event);
perf_event_update_userpage(event);
@@ -1610,7 +1611,6 @@ void x86_pmu_stop(struct perf_event *event, int flags)
if (test_bit(hwc->idx, cpuc->active_mask)) {
static_call(x86_pmu_disable)(event);
__clear_bit(hwc->idx, cpuc->active_mask);
- cpuc->events[hwc->idx] = NULL;
WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
hwc->state |= PERF_HES_STOPPED;
}
@@ -1648,6 +1648,7 @@ static void x86_pmu_del(struct perf_event *event, int flags)
* Not a TXN, therefore cleanup properly.
*/
x86_pmu_stop(event, PERF_EF_UPDATE);
+ cpuc->events[event->hw.idx] = NULL;
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event_list[i])
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss
2025-10-22 11:24 ` Peter Zijlstra
@ 2025-10-23 2:29 ` Mi, Dapeng
0 siblings, 0 replies; 22+ messages in thread
From: Mi, Dapeng @ 2025-10-23 2:29 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, kernel test robot,
Kan Liang
On 10/22/2025 7:24 PM, Peter Zijlstra wrote:
> On Wed, Oct 22, 2025 at 04:12:14PM +0800, Mi, Dapeng wrote:
>
>> Just think twice about this fix, it seems current fix is incomplete.
>> Besides the PEBS handler, the basic PMI handler could encounter same issue,
>> like the below code in handle_pmi_common(),
>>
>> for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
>> struct perf_event *event = cpuc->events[bit];
>> u64 last_period;
>>
>> handled++;
>>
>> if (!test_bit(bit, cpuc->active_mask))
>> continue;
>>
>> Although the NULL event would not be accessed by checking
>> the cpuc->active_mask, the potential overflow process of these NULL events
>> is skipped as well, it may cause data loss.
>>
>> Moreover, current approach defines temporary variables to snapshot the
>> active events, the temporary variables may consume too much stack memory
>> (384 bytes).
>>
>> So I enhance the fix as below. Do you have any comment on this? Thanks.
> So I didn't like the previous and I like this even less. What about
> something like this instead?
>
> I quickly went through the cpuc->event[ users and they all either check
> active_mask or, in case of the PEBS stuff, check pebs_enabled mask
> (which should be a subset of active_mask).
>
> (the PEBS last case depends on count being 0 for all counters that are
> not set in pebs_enabled)
Yes.
>
> WDYT?
>
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index 745caa6c15a3..74479f9d6eed 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -1344,6 +1344,7 @@ static void x86_pmu_enable(struct pmu *pmu)
> hwc->state |= PERF_HES_ARCH;
>
> x86_pmu_stop(event, PERF_EF_UPDATE);
> + cpuc->events[hwc->idx] = NULL;
> }
>
> /*
> @@ -1365,6 +1366,7 @@ static void x86_pmu_enable(struct pmu *pmu)
> * if cpuc->enabled = 0, then no wrmsr as
> * per x86_pmu_enable_event()
> */
> + cpuc->events[hwc->idx] = event;
> x86_pmu_start(event, PERF_EF_RELOAD);
> }
> cpuc->n_added = 0;
> @@ -1531,7 +1533,6 @@ static void x86_pmu_start(struct perf_event *event, int flags)
>
> event->hw.state = 0;
>
> - cpuc->events[idx] = event;
> __set_bit(idx, cpuc->active_mask);
> static_call(x86_pmu_enable)(event);
> perf_event_update_userpage(event);
> @@ -1610,7 +1611,6 @@ void x86_pmu_stop(struct perf_event *event, int flags)
> if (test_bit(hwc->idx, cpuc->active_mask)) {
> static_call(x86_pmu_disable)(event);
> __clear_bit(hwc->idx, cpuc->active_mask);
> - cpuc->events[hwc->idx] = NULL;
> WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
> hwc->state |= PERF_HES_STOPPED;
> }
> @@ -1648,6 +1648,7 @@ static void x86_pmu_del(struct perf_event *event, int flags)
> * Not a TXN, therefore cleanup properly.
> */
> x86_pmu_stop(event, PERF_EF_UPDATE);
> + cpuc->events[event->hw.idx] = NULL;
>
> for (i = 0; i < cpuc->n_events; i++) {
> if (event == cpuc->event_list[i])
This is a much prettier fix. Thanks.👍
It looks good to me. I did basic tests with this fix, and didn't find any
issues. But considering this is a such fundamental change, I would do more
tests later.
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [Patch v8 03/12] perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
2025-10-15 6:44 ` [Patch v8 01/12] perf/x86: Remove redundant is_x86_event() prototype Dapeng Mi
2025-10-15 6:44 ` [Patch v8 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 04/12] perf/x86/intel: Correct large PEBS flag check Dapeng Mi
` (8 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
Use x86_pmu_drain_pebs static call to replace calling x86_pmu.drain_pebs
function pointer.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 28f5468a6ea3..46a000eb0bb3 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3269,7 +3269,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status)
* The PEBS buffer has to be drained before handling the A-PMI
*/
if (is_pebs_counter_event_group(event))
- x86_pmu.drain_pebs(regs, &data);
+ static_call(x86_pmu_drain_pebs)(regs, &data);
last_period = event->hw.last_period;
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 04/12] perf/x86/intel: Correct large PEBS flag check
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (2 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 03/12] perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS Dapeng Mi
` (7 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
current large PEBS flag check only checks if sample_regs_user contains
unsupported GPRs but doesn't check if sample_regs_intr contains
unsupported GPRs.
Of course, currently PEBS HW supports to sample all perf supported GPRs,
the missed check doesn't cause real issue. But it won't be true any more
after the subsequent patches support to sample SSP register. SSP
sampling is not supported by adaptive PEBS HW and it would be supported
until arch-PEBS HW. So correct this issue.
Fixes: a47ba4d77e12 ("perf/x86: Enable free running PEBS for REGS_USER/INTR")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 46a000eb0bb3..c88bcd5d2bc4 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4029,7 +4029,9 @@ static unsigned long intel_pmu_large_pebs_flags(struct perf_event *event)
if (!event->attr.exclude_kernel)
flags &= ~PERF_SAMPLE_REGS_USER;
if (event->attr.sample_regs_user & ~PEBS_GP_REGS)
- flags &= ~(PERF_SAMPLE_REGS_USER | PERF_SAMPLE_REGS_INTR);
+ flags &= ~PERF_SAMPLE_REGS_USER;
+ if (event->attr.sample_regs_intr & ~PEBS_GP_REGS)
+ flags &= ~PERF_SAMPLE_REGS_INTR;
return flags;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (3 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 04/12] perf/x86/intel: Correct large PEBS flag check Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-21 15:43 ` Peter Zijlstra
2025-10-15 6:44 ` [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions Dapeng Mi
` (6 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
arch-PEBS leverages CPUID.23H.4/5 sub-leaves enumerate arch-PEBS
supported capabilities and counters bitmap. This patch parses these 2
sub-leaves and initializes arch-PEBS capabilities and corresponding
structures.
Since IA32_PEBS_ENABLE and MSR_PEBS_DATA_CFG MSRs are no longer existed
for arch-PEBS, arch-PEBS doesn't need to manipulate these MSRs. Thus add
a simple pair of __intel_pmu_pebs_enable/disable() callbacks for
arch-PEBS.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/core.c | 21 +++++++++---
arch/x86/events/intel/core.c | 55 +++++++++++++++++++++++--------
arch/x86/events/intel/ds.c | 52 ++++++++++++++++++++++++-----
arch/x86/events/perf_event.h | 25 ++++++++++++--
arch/x86/include/asm/perf_event.h | 7 +++-
5 files changed, 129 insertions(+), 31 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 745caa6c15a3..8c25ad2bf179 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -554,14 +554,22 @@ static inline int precise_br_compat(struct perf_event *event)
return m == b;
}
-int x86_pmu_max_precise(void)
+int x86_pmu_max_precise(struct pmu *pmu)
{
int precise = 0;
- /* Support for constant skid */
if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) {
- precise++;
+ /* arch PEBS */
+ if (x86_pmu.arch_pebs) {
+ precise = 2;
+ if (hybrid(pmu, arch_pebs_cap).pdists)
+ precise++;
+
+ return precise;
+ }
+ /* legacy PEBS - support for constant skid */
+ precise++;
/* Support for IP fixup */
if (x86_pmu.lbr_nr || x86_pmu.intel_cap.pebs_format >= 2)
precise++;
@@ -569,13 +577,14 @@ int x86_pmu_max_precise(void)
if (x86_pmu.pebs_prec_dist)
precise++;
}
+
return precise;
}
int x86_pmu_hw_config(struct perf_event *event)
{
if (event->attr.precise_ip) {
- int precise = x86_pmu_max_precise();
+ int precise = x86_pmu_max_precise(event->pmu);
if (event->attr.precise_ip > precise)
return -EOPNOTSUPP;
@@ -2629,7 +2638,9 @@ static ssize_t max_precise_show(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu_max_precise());
+ struct pmu *pmu = dev_get_drvdata(cdev);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu_max_precise(pmu));
}
static DEVICE_ATTR_RO(max_precise);
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index c88bcd5d2bc4..bfb123ff7c9a 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5273,34 +5273,58 @@ static inline bool intel_pmu_broken_perf_cap(void)
static void update_pmu_cap(struct pmu *pmu)
{
- unsigned int cntr, fixed_cntr, ecx, edx;
- union cpuid35_eax eax;
- union cpuid35_ebx ebx;
+ unsigned int eax, ebx, ecx, edx;
+ union cpuid35_eax eax_0;
+ union cpuid35_ebx ebx_0;
+ u64 cntrs_mask = 0;
+ u64 pebs_mask = 0;
+ u64 pdists_mask = 0;
- cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
+ cpuid(ARCH_PERFMON_EXT_LEAF, &eax_0.full, &ebx_0.full, &ecx, &edx);
- if (ebx.split.umask2)
+ if (ebx_0.split.umask2)
hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_UMASK2;
- if (ebx.split.eq)
+ if (ebx_0.split.eq)
hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_EQ;
- if (eax.split.cntr_subleaf) {
+ if (eax_0.split.cntr_subleaf) {
cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF,
- &cntr, &fixed_cntr, &ecx, &edx);
- hybrid(pmu, cntr_mask64) = cntr;
- hybrid(pmu, fixed_cntr_mask64) = fixed_cntr;
+ &eax, &ebx, &ecx, &edx);
+ hybrid(pmu, cntr_mask64) = eax;
+ hybrid(pmu, fixed_cntr_mask64) = ebx;
+ cntrs_mask = (u64)ebx << INTEL_PMC_IDX_FIXED | eax;
}
- if (eax.split.acr_subleaf) {
+ if (eax_0.split.acr_subleaf) {
cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_ACR_LEAF,
- &cntr, &fixed_cntr, &ecx, &edx);
+ &eax, &ebx, &ecx, &edx);
/* The mask of the counters which can be reloaded */
- hybrid(pmu, acr_cntr_mask64) = cntr | ((u64)fixed_cntr << INTEL_PMC_IDX_FIXED);
+ hybrid(pmu, acr_cntr_mask64) = eax | ((u64)ebx << INTEL_PMC_IDX_FIXED);
/* The mask of the counters which can cause a reload of reloadable counters */
hybrid(pmu, acr_cause_mask64) = ecx | ((u64)edx << INTEL_PMC_IDX_FIXED);
}
+ /* Bits[5:4] should be set simultaneously if arch-PEBS is supported */
+ if (eax_0.split.pebs_caps_subleaf && eax_0.split.pebs_cnts_subleaf) {
+ cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_CAP_LEAF,
+ &eax, &ebx, &ecx, &edx);
+ hybrid(pmu, arch_pebs_cap).caps = (u64)ebx << 32;
+
+ cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_COUNTER_LEAF,
+ &eax, &ebx, &ecx, &edx);
+ pebs_mask = ((u64)ecx << INTEL_PMC_IDX_FIXED) | eax;
+ pdists_mask = ((u64)edx << INTEL_PMC_IDX_FIXED) | ebx;
+ hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
+ hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
+
+ if (WARN_ON((pebs_mask | pdists_mask) & ~cntrs_mask))
+ x86_pmu.arch_pebs = 0;
+ } else {
+ WARN_ON(x86_pmu.arch_pebs == 1);
+ x86_pmu.arch_pebs = 0;
+ }
+
if (!intel_pmu_broken_perf_cap()) {
/* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
@@ -6252,7 +6276,7 @@ tsx_is_visible(struct kobject *kobj, struct attribute *attr, int i)
static umode_t
pebs_is_visible(struct kobject *kobj, struct attribute *attr, int i)
{
- return x86_pmu.ds_pebs ? attr->mode : 0;
+ return intel_pmu_has_pebs() ? attr->mode : 0;
}
static umode_t
@@ -7728,6 +7752,9 @@ __init int intel_pmu_init(void)
if (!is_hybrid() && boot_cpu_has(X86_FEATURE_ARCH_PERFMON_EXT))
update_pmu_cap(NULL);
+ if (x86_pmu.arch_pebs)
+ pr_cont("Architectural PEBS, ");
+
intel_pmu_check_counters_mask(&x86_pmu.cntr_mask64,
&x86_pmu.fixed_cntr_mask64,
&x86_pmu.intel_ctrl);
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 259a0ff807eb..a80881a20321 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1531,6 +1531,15 @@ static inline void intel_pmu_drain_large_pebs(struct cpu_hw_events *cpuc)
intel_pmu_drain_pebs_buffer();
}
+static void __intel_pmu_pebs_enable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+
+ hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
+ cpuc->pebs_enabled |= 1ULL << hwc->idx;
+}
+
void intel_pmu_pebs_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -1539,9 +1548,7 @@ void intel_pmu_pebs_enable(struct perf_event *event)
struct debug_store *ds = cpuc->ds;
unsigned int idx = hwc->idx;
- hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
-
- cpuc->pebs_enabled |= 1ULL << hwc->idx;
+ __intel_pmu_pebs_enable(event);
if ((event->hw.flags & PERF_X86_EVENT_PEBS_LDLAT) && (x86_pmu.version < 5))
cpuc->pebs_enabled |= 1ULL << (hwc->idx + 32);
@@ -1603,14 +1610,22 @@ void intel_pmu_pebs_del(struct perf_event *event)
pebs_update_state(needed_cb, cpuc, event, false);
}
-void intel_pmu_pebs_disable(struct perf_event *event)
+static void __intel_pmu_pebs_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
intel_pmu_drain_large_pebs(cpuc);
-
cpuc->pebs_enabled &= ~(1ULL << hwc->idx);
+ hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
+}
+
+void intel_pmu_pebs_disable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+
+ __intel_pmu_pebs_disable(event);
if ((event->hw.flags & PERF_X86_EVENT_PEBS_LDLAT) &&
(x86_pmu.version < 5))
@@ -1622,8 +1637,6 @@ void intel_pmu_pebs_disable(struct perf_event *event)
if (cpuc->enabled)
wrmsrq(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);
-
- hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
}
void intel_pmu_pebs_enable_all(void)
@@ -2695,11 +2708,26 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
}
}
+static void __init intel_arch_pebs_init(void)
+{
+ /*
+ * Current hybrid platforms always both support arch-PEBS or not
+ * on all kinds of cores. So directly set x86_pmu.arch_pebs flag
+ * if boot cpu supports arch-PEBS.
+ */
+ x86_pmu.arch_pebs = 1;
+ x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
+ x86_pmu.pebs_capable = ~0ULL;
+
+ x86_pmu.pebs_enable = __intel_pmu_pebs_enable;
+ x86_pmu.pebs_disable = __intel_pmu_pebs_disable;
+}
+
/*
* PEBS probe and setup
*/
-void __init intel_pebs_init(void)
+static void __init intel_ds_pebs_init(void)
{
/*
* No support for 32bit formats
@@ -2814,6 +2842,14 @@ void __init intel_pebs_init(void)
}
}
+void __init intel_pebs_init(void)
+{
+ if (x86_pmu.intel_cap.pebs_format == 0xf)
+ intel_arch_pebs_init();
+ else
+ intel_ds_pebs_init();
+}
+
void perf_restore_debug_store(void)
{
struct debug_store *ds = __this_cpu_read(cpu_hw_events.ds);
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 285779c73479..ca5289980b52 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -708,6 +708,12 @@ enum hybrid_pmu_type {
hybrid_big_small_tiny = hybrid_big | hybrid_small_tiny,
};
+struct arch_pebs_cap {
+ u64 caps;
+ u64 counters;
+ u64 pdists;
+};
+
struct x86_hybrid_pmu {
struct pmu pmu;
const char *name;
@@ -752,6 +758,8 @@ struct x86_hybrid_pmu {
mid_ack :1,
enabled_ack :1;
+ struct arch_pebs_cap arch_pebs_cap;
+
u64 pebs_data_source[PERF_PEBS_DATA_SOURCE_MAX];
};
@@ -906,7 +914,7 @@ struct x86_pmu {
union perf_capabilities intel_cap;
/*
- * Intel DebugStore bits
+ * Intel DebugStore and PEBS bits
*/
unsigned int bts :1,
bts_active :1,
@@ -917,7 +925,8 @@ struct x86_pmu {
pebs_no_tlb :1,
pebs_no_isolation :1,
pebs_block :1,
- pebs_ept :1;
+ pebs_ept :1,
+ arch_pebs :1;
int pebs_record_size;
int pebs_buffer_size;
u64 pebs_events_mask;
@@ -929,6 +938,11 @@ struct x86_pmu {
u64 rtm_abort_event;
u64 pebs_capable;
+ /*
+ * Intel Architectural PEBS
+ */
+ struct arch_pebs_cap arch_pebs_cap;
+
/*
* Intel LBR
*/
@@ -1216,7 +1230,7 @@ int x86_reserve_hardware(void);
void x86_release_hardware(void);
-int x86_pmu_max_precise(void);
+int x86_pmu_max_precise(struct pmu *pmu);
void hw_perf_lbr_event_destroy(struct perf_event *event);
@@ -1791,6 +1805,11 @@ static inline int intel_pmu_max_num_pebs(struct pmu *pmu)
return fls((u32)hybrid(pmu, pebs_events_mask));
}
+static inline bool intel_pmu_has_pebs(void)
+{
+ return x86_pmu.ds_pebs || x86_pmu.arch_pebs;
+}
+
#else /* CONFIG_CPU_SUP_INTEL */
static inline void reserve_ds_buffers(void)
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 49a4d442f3fc..0dfa06722bab 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -200,6 +200,8 @@ union cpuid10_edx {
#define ARCH_PERFMON_EXT_LEAF 0x00000023
#define ARCH_PERFMON_NUM_COUNTER_LEAF 0x1
#define ARCH_PERFMON_ACR_LEAF 0x2
+#define ARCH_PERFMON_PEBS_CAP_LEAF 0x4
+#define ARCH_PERFMON_PEBS_COUNTER_LEAF 0x5
union cpuid35_eax {
struct {
@@ -210,7 +212,10 @@ union cpuid35_eax {
unsigned int acr_subleaf:1;
/* Events Sub-Leaf */
unsigned int events_subleaf:1;
- unsigned int reserved:28;
+ /* arch-PEBS Sub-Leaves */
+ unsigned int pebs_caps_subleaf:1;
+ unsigned int pebs_cnts_subleaf:1;
+ unsigned int reserved:26;
} split;
unsigned int full;
};
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS
2025-10-15 6:44 ` [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS Dapeng Mi
@ 2025-10-21 15:43 ` Peter Zijlstra
2025-10-22 5:27 ` Mi, Dapeng
0 siblings, 1 reply; 22+ messages in thread
From: Peter Zijlstra @ 2025-10-21 15:43 UTC (permalink / raw)
To: Dapeng Mi
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi
On Wed, Oct 15, 2025 at 02:44:15PM +0800, Dapeng Mi wrote:
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index c88bcd5d2bc4..bfb123ff7c9a 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -5273,34 +5273,58 @@ static inline bool intel_pmu_broken_perf_cap(void)
>
> static void update_pmu_cap(struct pmu *pmu)
> {
> - unsigned int cntr, fixed_cntr, ecx, edx;
> - union cpuid35_eax eax;
> - union cpuid35_ebx ebx;
> + unsigned int eax, ebx, ecx, edx;
> + union cpuid35_eax eax_0;
> + union cpuid35_ebx ebx_0;
> + u64 cntrs_mask = 0;
> + u64 pebs_mask = 0;
> + u64 pdists_mask = 0;
>
> - cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
> + cpuid(ARCH_PERFMON_EXT_LEAF, &eax_0.full, &ebx_0.full, &ecx, &edx);
>
> - if (ebx.split.umask2)
> + if (ebx_0.split.umask2)
> hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_UMASK2;
> - if (ebx.split.eq)
> + if (ebx_0.split.eq)
> hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_EQ;
>
> - if (eax.split.cntr_subleaf) {
> + if (eax_0.split.cntr_subleaf) {
> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF,
> - &cntr, &fixed_cntr, &ecx, &edx);
> - hybrid(pmu, cntr_mask64) = cntr;
> - hybrid(pmu, fixed_cntr_mask64) = fixed_cntr;
> + &eax, &ebx, &ecx, &edx);
> + hybrid(pmu, cntr_mask64) = eax;
> + hybrid(pmu, fixed_cntr_mask64) = ebx;
> + cntrs_mask = (u64)ebx << INTEL_PMC_IDX_FIXED | eax;
> }
>
> - if (eax.split.acr_subleaf) {
> + if (eax_0.split.acr_subleaf) {
> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_ACR_LEAF,
> - &cntr, &fixed_cntr, &ecx, &edx);
> + &eax, &ebx, &ecx, &edx);
> /* The mask of the counters which can be reloaded */
> - hybrid(pmu, acr_cntr_mask64) = cntr | ((u64)fixed_cntr << INTEL_PMC_IDX_FIXED);
> + hybrid(pmu, acr_cntr_mask64) = eax | ((u64)ebx << INTEL_PMC_IDX_FIXED);
>
> /* The mask of the counters which can cause a reload of reloadable counters */
> hybrid(pmu, acr_cause_mask64) = ecx | ((u64)edx << INTEL_PMC_IDX_FIXED);
> }
>
> + /* Bits[5:4] should be set simultaneously if arch-PEBS is supported */
> + if (eax_0.split.pebs_caps_subleaf && eax_0.split.pebs_cnts_subleaf) {
> + cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_CAP_LEAF,
> + &eax, &ebx, &ecx, &edx);
> + hybrid(pmu, arch_pebs_cap).caps = (u64)ebx << 32;
> +
> + cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_COUNTER_LEAF,
> + &eax, &ebx, &ecx, &edx);
> + pebs_mask = ((u64)ecx << INTEL_PMC_IDX_FIXED) | eax;
> + pdists_mask = ((u64)edx << INTEL_PMC_IDX_FIXED) | ebx;
> + hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
> + hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
> +
> + if (WARN_ON((pebs_mask | pdists_mask) & ~cntrs_mask))
> + x86_pmu.arch_pebs = 0;
> + } else {
> + WARN_ON(x86_pmu.arch_pebs == 1);
> + x86_pmu.arch_pebs = 0;
> + }
> +
> if (!intel_pmu_broken_perf_cap()) {
> /* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
> rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
I've stuck this on top.
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5271,6 +5271,8 @@ static inline bool intel_pmu_broken_perf
return false;
}
+#define counter_mask(_gp, _fixed) ((_gp) | ((u64)(_fixed) << INTEL_PMC_IDX_FIXED))
+
static void update_pmu_cap(struct pmu *pmu)
{
unsigned int eax, ebx, ecx, edx;
@@ -5292,17 +5294,16 @@ static void update_pmu_cap(struct pmu *p
&eax, &ebx, &ecx, &edx);
hybrid(pmu, cntr_mask64) = eax;
hybrid(pmu, fixed_cntr_mask64) = ebx;
- cntrs_mask = (u64)ebx << INTEL_PMC_IDX_FIXED | eax;
+ cntrs_mask = counter_mask(eax, ebx);
}
if (eax_0.split.acr_subleaf) {
cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_ACR_LEAF,
&eax, &ebx, &ecx, &edx);
/* The mask of the counters which can be reloaded */
- hybrid(pmu, acr_cntr_mask64) = eax | ((u64)ebx << INTEL_PMC_IDX_FIXED);
-
+ hybrid(pmu, acr_cntr_mask64) = counter_mask(eax, ebx);
/* The mask of the counters which can cause a reload of reloadable counters */
- hybrid(pmu, acr_cause_mask64) = ecx | ((u64)edx << INTEL_PMC_IDX_FIXED);
+ hybrid(pmu, acr_cause_mask64) = counter_mask(ecx, edx);
}
/* Bits[5:4] should be set simultaneously if arch-PEBS is supported */
@@ -5313,8 +5314,8 @@ static void update_pmu_cap(struct pmu *p
cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_COUNTER_LEAF,
&eax, &ebx, &ecx, &edx);
- pebs_mask = ((u64)ecx << INTEL_PMC_IDX_FIXED) | eax;
- pdists_mask = ((u64)edx << INTEL_PMC_IDX_FIXED) | ebx;
+ pebs_mask = counter_mask(eax, ecx);
+ pdists_mask = counter_mask(ebx, edx);
hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS
2025-10-21 15:43 ` Peter Zijlstra
@ 2025-10-22 5:27 ` Mi, Dapeng
0 siblings, 0 replies; 22+ messages in thread
From: Mi, Dapeng @ 2025-10-22 5:27 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi
On 10/21/2025 11:43 PM, Peter Zijlstra wrote:
> On Wed, Oct 15, 2025 at 02:44:15PM +0800, Dapeng Mi wrote:
>> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
>> index c88bcd5d2bc4..bfb123ff7c9a 100644
>> --- a/arch/x86/events/intel/core.c
>> +++ b/arch/x86/events/intel/core.c
>> @@ -5273,34 +5273,58 @@ static inline bool intel_pmu_broken_perf_cap(void)
>>
>> static void update_pmu_cap(struct pmu *pmu)
>> {
>> - unsigned int cntr, fixed_cntr, ecx, edx;
>> - union cpuid35_eax eax;
>> - union cpuid35_ebx ebx;
>> + unsigned int eax, ebx, ecx, edx;
>> + union cpuid35_eax eax_0;
>> + union cpuid35_ebx ebx_0;
>> + u64 cntrs_mask = 0;
>> + u64 pebs_mask = 0;
>> + u64 pdists_mask = 0;
>>
>> - cpuid(ARCH_PERFMON_EXT_LEAF, &eax.full, &ebx.full, &ecx, &edx);
>> + cpuid(ARCH_PERFMON_EXT_LEAF, &eax_0.full, &ebx_0.full, &ecx, &edx);
>>
>> - if (ebx.split.umask2)
>> + if (ebx_0.split.umask2)
>> hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_UMASK2;
>> - if (ebx.split.eq)
>> + if (ebx_0.split.eq)
>> hybrid(pmu, config_mask) |= ARCH_PERFMON_EVENTSEL_EQ;
>>
>> - if (eax.split.cntr_subleaf) {
>> + if (eax_0.split.cntr_subleaf) {
>> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF,
>> - &cntr, &fixed_cntr, &ecx, &edx);
>> - hybrid(pmu, cntr_mask64) = cntr;
>> - hybrid(pmu, fixed_cntr_mask64) = fixed_cntr;
>> + &eax, &ebx, &ecx, &edx);
>> + hybrid(pmu, cntr_mask64) = eax;
>> + hybrid(pmu, fixed_cntr_mask64) = ebx;
>> + cntrs_mask = (u64)ebx << INTEL_PMC_IDX_FIXED | eax;
>> }
>>
>> - if (eax.split.acr_subleaf) {
>> + if (eax_0.split.acr_subleaf) {
>> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_ACR_LEAF,
>> - &cntr, &fixed_cntr, &ecx, &edx);
>> + &eax, &ebx, &ecx, &edx);
>> /* The mask of the counters which can be reloaded */
>> - hybrid(pmu, acr_cntr_mask64) = cntr | ((u64)fixed_cntr << INTEL_PMC_IDX_FIXED);
>> + hybrid(pmu, acr_cntr_mask64) = eax | ((u64)ebx << INTEL_PMC_IDX_FIXED);
>>
>> /* The mask of the counters which can cause a reload of reloadable counters */
>> hybrid(pmu, acr_cause_mask64) = ecx | ((u64)edx << INTEL_PMC_IDX_FIXED);
>> }
>>
>> + /* Bits[5:4] should be set simultaneously if arch-PEBS is supported */
>> + if (eax_0.split.pebs_caps_subleaf && eax_0.split.pebs_cnts_subleaf) {
>> + cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_CAP_LEAF,
>> + &eax, &ebx, &ecx, &edx);
>> + hybrid(pmu, arch_pebs_cap).caps = (u64)ebx << 32;
>> +
>> + cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_COUNTER_LEAF,
>> + &eax, &ebx, &ecx, &edx);
>> + pebs_mask = ((u64)ecx << INTEL_PMC_IDX_FIXED) | eax;
>> + pdists_mask = ((u64)edx << INTEL_PMC_IDX_FIXED) | ebx;
>> + hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
>> + hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
>> +
>> + if (WARN_ON((pebs_mask | pdists_mask) & ~cntrs_mask))
>> + x86_pmu.arch_pebs = 0;
>> + } else {
>> + WARN_ON(x86_pmu.arch_pebs == 1);
>> + x86_pmu.arch_pebs = 0;
>> + }
>> +
>> if (!intel_pmu_broken_perf_cap()) {
>> /* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
>> rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
> I've stuck this on top.
>
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -5271,6 +5271,8 @@ static inline bool intel_pmu_broken_perf
> return false;
> }
>
> +#define counter_mask(_gp, _fixed) ((_gp) | ((u64)(_fixed) << INTEL_PMC_IDX_FIXED))
> +
> static void update_pmu_cap(struct pmu *pmu)
> {
> unsigned int eax, ebx, ecx, edx;
> @@ -5292,17 +5294,16 @@ static void update_pmu_cap(struct pmu *p
> &eax, &ebx, &ecx, &edx);
> hybrid(pmu, cntr_mask64) = eax;
> hybrid(pmu, fixed_cntr_mask64) = ebx;
> - cntrs_mask = (u64)ebx << INTEL_PMC_IDX_FIXED | eax;
> + cntrs_mask = counter_mask(eax, ebx);
> }
>
> if (eax_0.split.acr_subleaf) {
> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_ACR_LEAF,
> &eax, &ebx, &ecx, &edx);
> /* The mask of the counters which can be reloaded */
> - hybrid(pmu, acr_cntr_mask64) = eax | ((u64)ebx << INTEL_PMC_IDX_FIXED);
> -
> + hybrid(pmu, acr_cntr_mask64) = counter_mask(eax, ebx);
> /* The mask of the counters which can cause a reload of reloadable counters */
> - hybrid(pmu, acr_cause_mask64) = ecx | ((u64)edx << INTEL_PMC_IDX_FIXED);
> + hybrid(pmu, acr_cause_mask64) = counter_mask(ecx, edx);
> }
>
> /* Bits[5:4] should be set simultaneously if arch-PEBS is supported */
> @@ -5313,8 +5314,8 @@ static void update_pmu_cap(struct pmu *p
>
> cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_PEBS_COUNTER_LEAF,
> &eax, &ebx, &ecx, &edx);
> - pebs_mask = ((u64)ecx << INTEL_PMC_IDX_FIXED) | eax;
> - pdists_mask = ((u64)edx << INTEL_PMC_IDX_FIXED) | ebx;
> + pebs_mask = counter_mask(eax, ecx);
> + pdists_mask = counter_mask(ebx, edx);
> hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
> hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
Nice suggestion. Would do. Thanks.
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (4 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 05/12] perf/x86/intel: Initialize architectural PEBS Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-21 15:49 ` Peter Zijlstra
2025-10-22 11:49 ` Peter Zijlstra
2025-10-15 6:44 ` [Patch v8 07/12] perf/x86/intel/ds: Factor out PEBS group " Dapeng Mi
` (5 subsequent siblings)
11 siblings, 2 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi, Kan Liang
Beside some PEBS record layout difference, arch-PEBS can share most of
PEBS record processing code with adaptive PEBS. Thus, factor out these
common processing code to independent inline functions, so they can be
reused by subsequent arch-PEBS handler.
Suggested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/ds.c | 101 ++++++++++++++++++++++++-------------
1 file changed, 66 insertions(+), 35 deletions(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index a80881a20321..41acbf0a11c9 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2629,6 +2629,64 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
}
}
+static inline void __intel_pmu_handle_pebs_record(struct pt_regs *iregs,
+ struct pt_regs *regs,
+ struct perf_sample_data *data,
+ void *at, u64 pebs_status,
+ struct perf_event *events[],
+ short *counts, void **last,
+ setup_fn setup_sample)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct perf_event *event;
+ int bit;
+
+ for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
+ event = cpuc->events[bit];
+
+ if (WARN_ON_ONCE(!event) ||
+ WARN_ON_ONCE(!event->attr.precise_ip))
+ continue;
+
+ if (counts[bit]++)
+ __intel_pmu_pebs_event(event, iregs, regs, data,
+ last[bit], setup_sample);
+
+ last[bit] = at;
+ /*
+ * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
+ * could trigger interrupt throttle and clear all event pointers of
+ * the group in cpuc->events[] to NULL. So snapshot the event[] before
+ * it could be cleared. This avoids the possible NULL event pointer
+ * access and PEBS record loss.
+ */
+ if (counts[bit] && !events[bit])
+ events[bit] = cpuc->events[bit];
+ }
+}
+
+static inline void
+__intel_pmu_handle_last_pebs_record(struct pt_regs *iregs, struct pt_regs *regs,
+ struct perf_sample_data *data, u64 mask,
+ struct perf_event *events[],
+ short *counts, void **last,
+ setup_fn setup_sample)
+{
+ struct perf_event *event;
+ int bit;
+
+ for_each_set_bit(bit, (unsigned long *)&mask, X86_PMC_IDX_MAX) {
+ if (!counts[bit])
+ continue;
+
+ event = events[bit];
+
+ __intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
+ counts[bit], setup_sample);
+ }
+
+}
+
static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_data *data)
{
struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
@@ -2639,9 +2697,7 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
struct pebs_basic *basic;
- struct perf_event *event;
void *base, *at, *top;
- int bit;
u64 mask;
if (!x86_pmu.pebs_active)
@@ -2654,6 +2710,7 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
mask = hybrid(cpuc->pmu, pebs_events_mask) |
(hybrid(cpuc->pmu, fixed_cntr_mask64) << INTEL_PMC_IDX_FIXED);
+ mask &= cpuc->pebs_enabled;
if (unlikely(base >= top)) {
intel_pmu_pebs_event_update_no_drain(cpuc, mask);
@@ -2671,41 +2728,15 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
if (basic->format_size != cpuc->pebs_record_size)
continue;
- pebs_status = basic->applicable_counters & cpuc->pebs_enabled & mask;
- for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
- event = cpuc->events[bit];
-
- if (WARN_ON_ONCE(!event) ||
- WARN_ON_ONCE(!event->attr.precise_ip))
- continue;
-
- if (counts[bit]++) {
- __intel_pmu_pebs_event(event, iregs, regs, data, last[bit],
- setup_pebs_adaptive_sample_data);
- }
- last[bit] = at;
-
- /*
- * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
- * could trigger interrupt throttle and clear all event pointers of
- * the group in cpuc->events[] to NULL. So snapshot the event[] before
- * it could be cleared. This avoids the possible NULL event pointer
- * access and PEBS record loss.
- */
- if (counts[bit] && !events[bit])
- events[bit] = cpuc->events[bit];
- }
+ pebs_status = mask & basic->applicable_counters;
+ __intel_pmu_handle_pebs_record(iregs, regs, data, at,
+ pebs_status, events, counts, last,
+ setup_pebs_adaptive_sample_data);
}
- for_each_set_bit(bit, (unsigned long *)&mask, X86_PMC_IDX_MAX) {
- if (!counts[bit])
- continue;
-
- event = events[bit];
-
- __intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
- counts[bit], setup_pebs_adaptive_sample_data);
- }
+ __intel_pmu_handle_last_pebs_record(iregs, regs, data, mask, events,
+ counts, last,
+ setup_pebs_adaptive_sample_data);
}
static void __init intel_arch_pebs_init(void)
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions
2025-10-15 6:44 ` [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions Dapeng Mi
@ 2025-10-21 15:49 ` Peter Zijlstra
2025-10-22 5:32 ` Mi, Dapeng
2025-10-22 11:49 ` Peter Zijlstra
1 sibling, 1 reply; 22+ messages in thread
From: Peter Zijlstra @ 2025-10-21 15:49 UTC (permalink / raw)
To: Dapeng Mi
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, Kan Liang
On Wed, Oct 15, 2025 at 02:44:16PM +0800, Dapeng Mi wrote:
> +static inline void __intel_pmu_handle_pebs_record(struct pt_regs *iregs,
> + struct pt_regs *regs,
> + struct perf_sample_data *data,
> + void *at, u64 pebs_status,
> + struct perf_event *events[],
> + short *counts, void **last,
> + setup_fn setup_sample)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + struct perf_event *event;
> + int bit;
> +
> + for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
> + event = cpuc->events[bit];
> +
> + if (WARN_ON_ONCE(!event) ||
> + WARN_ON_ONCE(!event->attr.precise_ip))
> + continue;
> +
> + if (counts[bit]++)
> + __intel_pmu_pebs_event(event, iregs, regs, data,
> + last[bit], setup_sample);
No brackets, while coding style requires.
> +
> + last[bit] = at;
> + /*
> + * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
> + * could trigger interrupt throttle and clear all event pointers of
> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
> + * it could be cleared. This avoids the possible NULL event pointer
> + * access and PEBS record loss.
> + */
> + if (counts[bit] && !events[bit])
> + events[bit] = cpuc->events[bit];
> + }
> +}
> @@ -2671,41 +2728,15 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
> if (basic->format_size != cpuc->pebs_record_size)
> continue;
>
> - pebs_status = basic->applicable_counters & cpuc->pebs_enabled & mask;
> - for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
> - event = cpuc->events[bit];
> -
> - if (WARN_ON_ONCE(!event) ||
> - WARN_ON_ONCE(!event->attr.precise_ip))
> - continue;
> -
> - if (counts[bit]++) {
> - __intel_pmu_pebs_event(event, iregs, regs, data, last[bit],
> - setup_pebs_adaptive_sample_data);
> - }
Brackets. Which suggests you took effort to remove them, since cut-paste
code movement would've preserved them.
I've re-instated them.
> - last[bit] = at;
> -
> - /*
> - * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
> - * could trigger interrupt throttle and clear all event pointers of
> - * the group in cpuc->events[] to NULL. So snapshot the event[] before
> - * it could be cleared. This avoids the possible NULL event pointer
> - * access and PEBS record loss.
> - */
> - if (counts[bit] && !events[bit])
> - events[bit] = cpuc->events[bit];
> - }
> + pebs_status = mask & basic->applicable_counters;
> + __intel_pmu_handle_pebs_record(iregs, regs, data, at,
> + pebs_status, events, counts, last,
> + setup_pebs_adaptive_sample_data);
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions
2025-10-21 15:49 ` Peter Zijlstra
@ 2025-10-22 5:32 ` Mi, Dapeng
0 siblings, 0 replies; 22+ messages in thread
From: Mi, Dapeng @ 2025-10-22 5:32 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, Kan Liang
On 10/21/2025 11:49 PM, Peter Zijlstra wrote:
> On Wed, Oct 15, 2025 at 02:44:16PM +0800, Dapeng Mi wrote:
>
>> +static inline void __intel_pmu_handle_pebs_record(struct pt_regs *iregs,
>> + struct pt_regs *regs,
>> + struct perf_sample_data *data,
>> + void *at, u64 pebs_status,
>> + struct perf_event *events[],
>> + short *counts, void **last,
>> + setup_fn setup_sample)
>> +{
>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>> + struct perf_event *event;
>> + int bit;
>> +
>> + for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
>> + event = cpuc->events[bit];
>> +
>> + if (WARN_ON_ONCE(!event) ||
>> + WARN_ON_ONCE(!event->attr.precise_ip))
>> + continue;
>> +
>> + if (counts[bit]++)
>> + __intel_pmu_pebs_event(event, iregs, regs, data,
>> + last[bit], setup_sample);
> No brackets, while coding style requires.
Sure. Not sure why checkpatch.pl doesn't found it. Thanks.
>
>> +
>> + last[bit] = at;
>> + /*
>> + * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
>> + * could trigger interrupt throttle and clear all event pointers of
>> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
>> + * it could be cleared. This avoids the possible NULL event pointer
>> + * access and PEBS record loss.
>> + */
>> + if (counts[bit] && !events[bit])
>> + events[bit] = cpuc->events[bit];
>> + }
>> +}
>
>> @@ -2671,41 +2728,15 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
>> if (basic->format_size != cpuc->pebs_record_size)
>> continue;
>>
>> - pebs_status = basic->applicable_counters & cpuc->pebs_enabled & mask;
>> - for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
>> - event = cpuc->events[bit];
>> -
>> - if (WARN_ON_ONCE(!event) ||
>> - WARN_ON_ONCE(!event->attr.precise_ip))
>> - continue;
>> -
>> - if (counts[bit]++) {
>> - __intel_pmu_pebs_event(event, iregs, regs, data, last[bit],
>> - setup_pebs_adaptive_sample_data);
>> - }
> Brackets. Which suggests you took effort to remove them, since cut-paste
> code movement would've preserved them.
>
> I've re-instated them.
>
>> - last[bit] = at;
>> -
>> - /*
>> - * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
>> - * could trigger interrupt throttle and clear all event pointers of
>> - * the group in cpuc->events[] to NULL. So snapshot the event[] before
>> - * it could be cleared. This avoids the possible NULL event pointer
>> - * access and PEBS record loss.
>> - */
>> - if (counts[bit] && !events[bit])
>> - events[bit] = cpuc->events[bit];
>> - }
>> + pebs_status = mask & basic->applicable_counters;
>> + __intel_pmu_handle_pebs_record(iregs, regs, data, at,
>> + pebs_status, events, counts, last,
>> + setup_pebs_adaptive_sample_data);
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions
2025-10-15 6:44 ` [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions Dapeng Mi
2025-10-21 15:49 ` Peter Zijlstra
@ 2025-10-22 11:49 ` Peter Zijlstra
2025-10-23 1:06 ` Mi, Dapeng
1 sibling, 1 reply; 22+ messages in thread
From: Peter Zijlstra @ 2025-10-22 11:49 UTC (permalink / raw)
To: Dapeng Mi
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, Kan Liang
On Wed, Oct 15, 2025 at 02:44:16PM +0800, Dapeng Mi wrote:
> Beside some PEBS record layout difference, arch-PEBS can share most of
> PEBS record processing code with adaptive PEBS. Thus, factor out these
> common processing code to independent inline functions, so they can be
> reused by subsequent arch-PEBS handler.
>
> Suggested-by: Kan Liang <kan.liang@linux.intel.com>
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
> arch/x86/events/intel/ds.c | 101 ++++++++++++++++++++++++-------------
> 1 file changed, 66 insertions(+), 35 deletions(-)
>
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index a80881a20321..41acbf0a11c9 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -2629,6 +2629,64 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
> }
> }
>
> +static inline void __intel_pmu_handle_pebs_record(struct pt_regs *iregs,
> + struct pt_regs *regs,
> + struct perf_sample_data *data,
> + void *at, u64 pebs_status,
> + struct perf_event *events[],
> + short *counts, void **last,
> + setup_fn setup_sample)
> +{
> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
> + struct perf_event *event;
> + int bit;
> +
> + for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
> + event = cpuc->events[bit];
> +
> + if (WARN_ON_ONCE(!event) ||
> + WARN_ON_ONCE(!event->attr.precise_ip))
> + continue;
> +
> + if (counts[bit]++)
> + __intel_pmu_pebs_event(event, iregs, regs, data,
> + last[bit], setup_sample);
> +
> + last[bit] = at;
> + /*
> + * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
> + * could trigger interrupt throttle and clear all event pointers of
> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
> + * it could be cleared. This avoids the possible NULL event pointer
> + * access and PEBS record loss.
> + */
> + if (counts[bit] && !events[bit])
> + events[bit] = cpuc->events[bit];
> + }
> +}
> +
> +static inline void
> +__intel_pmu_handle_last_pebs_record(struct pt_regs *iregs, struct pt_regs *regs,
> + struct perf_sample_data *data, u64 mask,
> + struct perf_event *events[],
> + short *counts, void **last,
> + setup_fn setup_sample)
> +{
> + struct perf_event *event;
> + int bit;
> +
> + for_each_set_bit(bit, (unsigned long *)&mask, X86_PMC_IDX_MAX) {
> + if (!counts[bit])
> + continue;
> +
> + event = events[bit];
> +
> + __intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
> + counts[bit], setup_sample);
> + }
> +
> +}
These need to be __always_inline, like the other functions that take
setup_fn. Otherwise the compiler might decide to not inline and then it
can't constant propagate this function and we get indirect calls.
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions
2025-10-22 11:49 ` Peter Zijlstra
@ 2025-10-23 1:06 ` Mi, Dapeng
0 siblings, 0 replies; 22+ messages in thread
From: Mi, Dapeng @ 2025-10-23 1:06 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Ian Rogers,
Adrian Hunter, Alexander Shishkin, Andi Kleen, Eranian Stephane,
linux-kernel, linux-perf-users, Dapeng Mi, Kan Liang
On 10/22/2025 7:49 PM, Peter Zijlstra wrote:
> On Wed, Oct 15, 2025 at 02:44:16PM +0800, Dapeng Mi wrote:
>> Beside some PEBS record layout difference, arch-PEBS can share most of
>> PEBS record processing code with adaptive PEBS. Thus, factor out these
>> common processing code to independent inline functions, so they can be
>> reused by subsequent arch-PEBS handler.
>>
>> Suggested-by: Kan Liang <kan.liang@linux.intel.com>
>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>> ---
>> arch/x86/events/intel/ds.c | 101 ++++++++++++++++++++++++-------------
>> 1 file changed, 66 insertions(+), 35 deletions(-)
>>
>> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
>> index a80881a20321..41acbf0a11c9 100644
>> --- a/arch/x86/events/intel/ds.c
>> +++ b/arch/x86/events/intel/ds.c
>> @@ -2629,6 +2629,64 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
>> }
>> }
>>
>> +static inline void __intel_pmu_handle_pebs_record(struct pt_regs *iregs,
>> + struct pt_regs *regs,
>> + struct perf_sample_data *data,
>> + void *at, u64 pebs_status,
>> + struct perf_event *events[],
>> + short *counts, void **last,
>> + setup_fn setup_sample)
>> +{
>> + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
>> + struct perf_event *event;
>> + int bit;
>> +
>> + for_each_set_bit(bit, (unsigned long *)&pebs_status, X86_PMC_IDX_MAX) {
>> + event = cpuc->events[bit];
>> +
>> + if (WARN_ON_ONCE(!event) ||
>> + WARN_ON_ONCE(!event->attr.precise_ip))
>> + continue;
>> +
>> + if (counts[bit]++)
>> + __intel_pmu_pebs_event(event, iregs, regs, data,
>> + last[bit], setup_sample);
>> +
>> + last[bit] = at;
>> + /*
>> + * perf_event_overflow() called by below __intel_pmu_pebs_last_event()
>> + * could trigger interrupt throttle and clear all event pointers of
>> + * the group in cpuc->events[] to NULL. So snapshot the event[] before
>> + * it could be cleared. This avoids the possible NULL event pointer
>> + * access and PEBS record loss.
>> + */
>> + if (counts[bit] && !events[bit])
>> + events[bit] = cpuc->events[bit];
>> + }
>> +}
>> +
>> +static inline void
>> +__intel_pmu_handle_last_pebs_record(struct pt_regs *iregs, struct pt_regs *regs,
>> + struct perf_sample_data *data, u64 mask,
>> + struct perf_event *events[],
>> + short *counts, void **last,
>> + setup_fn setup_sample)
>> +{
>> + struct perf_event *event;
>> + int bit;
>> +
>> + for_each_set_bit(bit, (unsigned long *)&mask, X86_PMC_IDX_MAX) {
>> + if (!counts[bit])
>> + continue;
>> +
>> + event = events[bit];
>> +
>> + __intel_pmu_pebs_last_event(event, iregs, regs, data, last[bit],
>> + counts[bit], setup_sample);
>> + }
>> +
>> +}
> These need to be __always_inline, like the other functions that take
> setup_fn. Otherwise the compiler might decide to not inline and then it
> can't constant propagate this function and we get indirect calls.
Indeed. Would change it. Thanks.
>
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [Patch v8 07/12] perf/x86/intel/ds: Factor out PEBS group processing code to functions
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (5 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 06/12] perf/x86/intel/ds: Factor out PEBS record processing code to functions Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 08/12] perf/x86/intel: Process arch-PEBS records or record fragments Dapeng Mi
` (4 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
Adaptive PEBS and arch-PEBS share lots of same code to process these
PEBS groups, like basic, GPR and meminfo groups. Extract these shared
code to generic functions to avoid duplicated code.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/ds.c | 170 +++++++++++++++++++++++--------------
1 file changed, 104 insertions(+), 66 deletions(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 41acbf0a11c9..d5441fca8d63 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2072,6 +2072,90 @@ static inline void __setup_pebs_counter_group(struct cpu_hw_events *cpuc,
#define PEBS_LATENCY_MASK 0xffff
+static inline void __setup_perf_sample_data(struct perf_event *event,
+ struct pt_regs *iregs,
+ struct perf_sample_data *data)
+{
+ perf_sample_data_init(data, 0, event->hw.last_period);
+
+ /*
+ * We must however always use iregs for the unwinder to stay sane; the
+ * record BP,SP,IP can point into thin air when the record is from a
+ * previous PMI context or an (I)RET happened between the record and
+ * PMI.
+ */
+ perf_sample_save_callchain(data, event, iregs);
+}
+
+static inline void __setup_pebs_basic_group(struct perf_event *event,
+ struct pt_regs *regs,
+ struct perf_sample_data *data,
+ u64 sample_type, u64 ip,
+ u64 tsc, u16 retire)
+{
+ /* The ip in basic is EventingIP */
+ set_linear_ip(regs, ip);
+ regs->flags = PERF_EFLAGS_EXACT;
+ setup_pebs_time(event, data, tsc);
+
+ if (sample_type & PERF_SAMPLE_WEIGHT_STRUCT)
+ data->weight.var3_w = retire;
+}
+
+static inline void __setup_pebs_gpr_group(struct perf_event *event,
+ struct pt_regs *regs,
+ struct pebs_gprs *gprs,
+ u64 sample_type)
+{
+ if (event->attr.precise_ip < 2) {
+ set_linear_ip(regs, gprs->ip);
+ regs->flags &= ~PERF_EFLAGS_EXACT;
+ }
+
+ if (sample_type & (PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER))
+ adaptive_pebs_save_regs(regs, gprs);
+}
+
+static inline void __setup_pebs_meminfo_group(struct perf_event *event,
+ struct perf_sample_data *data,
+ u64 sample_type, u64 latency,
+ u16 instr_latency, u64 address,
+ u64 aux, u64 tsx_tuning, u64 ax)
+{
+ if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
+ u64 tsx_latency = intel_get_tsx_weight(tsx_tuning);
+
+ data->weight.var2_w = instr_latency;
+
+ /*
+ * Although meminfo::latency is defined as a u64,
+ * only the lower 32 bits include the valid data
+ * in practice on Ice Lake and earlier platforms.
+ */
+ if (sample_type & PERF_SAMPLE_WEIGHT)
+ data->weight.full = latency ?: tsx_latency;
+ else
+ data->weight.var1_dw = (u32)latency ?: tsx_latency;
+
+ data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
+ }
+
+ if (sample_type & PERF_SAMPLE_DATA_SRC) {
+ data->data_src.val = get_data_src(event, aux);
+ data->sample_flags |= PERF_SAMPLE_DATA_SRC;
+ }
+
+ if (sample_type & PERF_SAMPLE_ADDR_TYPE) {
+ data->addr = address;
+ data->sample_flags |= PERF_SAMPLE_ADDR;
+ }
+
+ if (sample_type & PERF_SAMPLE_TRANSACTION) {
+ data->txn = intel_get_tsx_transaction(tsx_tuning, ax);
+ data->sample_flags |= PERF_SAMPLE_TRANSACTION;
+ }
+}
+
/*
* With adaptive PEBS the layout depends on what fields are configured.
*/
@@ -2081,12 +2165,14 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
struct pt_regs *regs)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ u64 sample_type = event->attr.sample_type;
struct pebs_basic *basic = __pebs;
void *next_record = basic + 1;
- u64 sample_type, format_group;
struct pebs_meminfo *meminfo = NULL;
struct pebs_gprs *gprs = NULL;
struct x86_perf_regs *perf_regs;
+ u64 format_group;
+ u16 retire;
if (basic == NULL)
return;
@@ -2094,31 +2180,17 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
perf_regs = container_of(regs, struct x86_perf_regs, regs);
perf_regs->xmm_regs = NULL;
- sample_type = event->attr.sample_type;
format_group = basic->format_group;
- perf_sample_data_init(data, 0, event->hw.last_period);
- setup_pebs_time(event, data, basic->tsc);
-
- /*
- * We must however always use iregs for the unwinder to stay sane; the
- * record BP,SP,IP can point into thin air when the record is from a
- * previous PMI context or an (I)RET happened between the record and
- * PMI.
- */
- perf_sample_save_callchain(data, event, iregs);
+ __setup_perf_sample_data(event, iregs, data);
*regs = *iregs;
- /* The ip in basic is EventingIP */
- set_linear_ip(regs, basic->ip);
- regs->flags = PERF_EFLAGS_EXACT;
- if (sample_type & PERF_SAMPLE_WEIGHT_STRUCT) {
- if (x86_pmu.flags & PMU_FL_RETIRE_LATENCY)
- data->weight.var3_w = basic->retire_latency;
- else
- data->weight.var3_w = 0;
- }
+ /* basic group */
+ retire = x86_pmu.flags & PMU_FL_RETIRE_LATENCY ?
+ basic->retire_latency : 0;
+ __setup_pebs_basic_group(event, regs, data, sample_type,
+ basic->ip, basic->tsc, retire);
/*
* The record for MEMINFO is in front of GP
@@ -2134,54 +2206,20 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
gprs = next_record;
next_record = gprs + 1;
- if (event->attr.precise_ip < 2) {
- set_linear_ip(regs, gprs->ip);
- regs->flags &= ~PERF_EFLAGS_EXACT;
- }
-
- if (sample_type & (PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER))
- adaptive_pebs_save_regs(regs, gprs);
+ __setup_pebs_gpr_group(event, regs, gprs, sample_type);
}
if (format_group & PEBS_DATACFG_MEMINFO) {
- if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
- u64 latency = x86_pmu.flags & PMU_FL_INSTR_LATENCY ?
- meminfo->cache_latency : meminfo->mem_latency;
-
- if (x86_pmu.flags & PMU_FL_INSTR_LATENCY)
- data->weight.var2_w = meminfo->instr_latency;
-
- /*
- * Although meminfo::latency is defined as a u64,
- * only the lower 32 bits include the valid data
- * in practice on Ice Lake and earlier platforms.
- */
- if (sample_type & PERF_SAMPLE_WEIGHT) {
- data->weight.full = latency ?:
- intel_get_tsx_weight(meminfo->tsx_tuning);
- } else {
- data->weight.var1_dw = (u32)latency ?:
- intel_get_tsx_weight(meminfo->tsx_tuning);
- }
-
- data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
- }
-
- if (sample_type & PERF_SAMPLE_DATA_SRC) {
- data->data_src.val = get_data_src(event, meminfo->aux);
- data->sample_flags |= PERF_SAMPLE_DATA_SRC;
- }
-
- if (sample_type & PERF_SAMPLE_ADDR_TYPE) {
- data->addr = meminfo->address;
- data->sample_flags |= PERF_SAMPLE_ADDR;
- }
-
- if (sample_type & PERF_SAMPLE_TRANSACTION) {
- data->txn = intel_get_tsx_transaction(meminfo->tsx_tuning,
- gprs ? gprs->ax : 0);
- data->sample_flags |= PERF_SAMPLE_TRANSACTION;
- }
+ u64 latency = x86_pmu.flags & PMU_FL_INSTR_LATENCY ?
+ meminfo->cache_latency : meminfo->mem_latency;
+ u64 instr_latency = x86_pmu.flags & PMU_FL_INSTR_LATENCY ?
+ meminfo->instr_latency : 0;
+ u64 ax = gprs ? gprs->ax : 0;
+
+ __setup_pebs_meminfo_group(event, data, sample_type, latency,
+ instr_latency, meminfo->address,
+ meminfo->aux, meminfo->tsx_tuning,
+ ax);
}
if (format_group & PEBS_DATACFG_XMMS) {
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 08/12] perf/x86/intel: Process arch-PEBS records or record fragments
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (6 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 07/12] perf/x86/intel/ds: Factor out PEBS group " Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 09/12] perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR Dapeng Mi
` (3 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
A significant difference with adaptive PEBS is that arch-PEBS record
supports fragments which means an arch-PEBS record could be split into
several independent fragments which have its own arch-PEBS header in
each fragment.
This patch defines architectural PEBS record layout structures and add
helpers to process arch-PEBS records or fragments. Only legacy PEBS
groups like basic, GPR, XMM and LBR groups are supported in this patch,
the new added YMM/ZMM/OPMASK vector registers capturing would be
supported in the future.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 13 +++
arch/x86/events/intel/ds.c | 182 ++++++++++++++++++++++++++++++
arch/x86/include/asm/msr-index.h | 6 +
arch/x86/include/asm/perf_event.h | 96 ++++++++++++++++
4 files changed, 297 insertions(+)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index bfb123ff7c9a..cab2ce73ad09 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3215,6 +3215,19 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status)
status &= ~GLOBAL_STATUS_PERF_METRICS_OVF_BIT;
}
+ /*
+ * Arch PEBS sets bit 54 in the global status register
+ */
+ if (__test_and_clear_bit(GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT,
+ (unsigned long *)&status)) {
+ handled++;
+ static_call(x86_pmu_drain_pebs)(regs, &data);
+
+ if (cpuc->events[INTEL_PMC_IDX_FIXED_SLOTS] &&
+ is_pebs_counter_event_group(cpuc->events[INTEL_PMC_IDX_FIXED_SLOTS]))
+ status &= ~GLOBAL_STATUS_PERF_METRICS_OVF_BIT;
+ }
+
/*
* Intel PT
*/
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index d5441fca8d63..651f3709c260 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2270,6 +2270,114 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
format_group);
}
+static inline bool arch_pebs_record_continued(struct arch_pebs_header *header)
+{
+ /* Continue bit or null PEBS record indicates fragment follows. */
+ return header->cont || !(header->format & GENMASK_ULL(63, 16));
+}
+
+static void setup_arch_pebs_sample_data(struct perf_event *event,
+ struct pt_regs *iregs, void *__pebs,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ u64 sample_type = event->attr.sample_type;
+ struct arch_pebs_header *header = NULL;
+ struct arch_pebs_aux *meminfo = NULL;
+ struct arch_pebs_gprs *gprs = NULL;
+ struct x86_perf_regs *perf_regs;
+ void *next_record;
+ void *at = __pebs;
+
+ if (at == NULL)
+ return;
+
+ perf_regs = container_of(regs, struct x86_perf_regs, regs);
+ perf_regs->xmm_regs = NULL;
+
+ __setup_perf_sample_data(event, iregs, data);
+
+ *regs = *iregs;
+
+again:
+ header = at;
+ next_record = at + sizeof(struct arch_pebs_header);
+ if (header->basic) {
+ struct arch_pebs_basic *basic = next_record;
+ u16 retire = 0;
+
+ next_record = basic + 1;
+
+ if (sample_type & PERF_SAMPLE_WEIGHT_STRUCT)
+ retire = basic->valid ? basic->retire : 0;
+ __setup_pebs_basic_group(event, regs, data, sample_type,
+ basic->ip, basic->tsc, retire);
+ }
+
+ /*
+ * The record for MEMINFO is in front of GP
+ * But PERF_SAMPLE_TRANSACTION needs gprs->ax.
+ * Save the pointer here but process later.
+ */
+ if (header->aux) {
+ meminfo = next_record;
+ next_record = meminfo + 1;
+ }
+
+ if (header->gpr) {
+ gprs = next_record;
+ next_record = gprs + 1;
+
+ __setup_pebs_gpr_group(event, regs, (struct pebs_gprs *)gprs,
+ sample_type);
+ }
+
+ if (header->aux) {
+ u64 ax = gprs ? gprs->ax : 0;
+
+ __setup_pebs_meminfo_group(event, data, sample_type,
+ meminfo->cache_latency,
+ meminfo->instr_latency,
+ meminfo->address, meminfo->aux,
+ meminfo->tsx_tuning, ax);
+ }
+
+ if (header->xmm) {
+ struct pebs_xmm *xmm;
+
+ next_record += sizeof(struct arch_pebs_xer_header);
+
+ xmm = next_record;
+ perf_regs->xmm_regs = xmm->xmm;
+ next_record = xmm + 1;
+ }
+
+ if (header->lbr) {
+ struct arch_pebs_lbr_header *lbr_header = next_record;
+ struct lbr_entry *lbr;
+ int num_lbr;
+
+ next_record = lbr_header + 1;
+ lbr = next_record;
+
+ num_lbr = header->lbr == ARCH_PEBS_LBR_NUM_VAR ? lbr_header->depth :
+ header->lbr * ARCH_PEBS_BASE_LBR_ENTRIES;
+ next_record += num_lbr * sizeof(struct lbr_entry);
+
+ if (has_branch_stack(event)) {
+ intel_pmu_store_pebs_lbrs(lbr);
+ intel_pmu_lbr_save_brstack(data, cpuc, event);
+ }
+ }
+
+ /* Parse followed fragments if there are. */
+ if (arch_pebs_record_continued(header)) {
+ at = at + header->size;
+ goto again;
+ }
+}
+
static inline void *
get_next_pebs_record_by_bit(void *base, void *top, int bit)
{
@@ -2777,6 +2885,79 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
setup_pebs_adaptive_sample_data);
}
+static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
+ struct perf_sample_data *data)
+{
+ struct perf_event *events[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {NULL};
+ short counts[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {};
+ void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ union arch_pebs_index index;
+ struct x86_perf_regs perf_regs;
+ struct pt_regs *regs = &perf_regs.regs;
+ void *base, *at, *top;
+ u64 mask;
+
+ rdmsrq(MSR_IA32_PEBS_INDEX, index.whole);
+
+ if (unlikely(!index.wr)) {
+ intel_pmu_pebs_event_update_no_drain(cpuc, X86_PMC_IDX_MAX);
+ return;
+ }
+
+ base = cpuc->ds_pebs_vaddr;
+ top = (void *)((u64)cpuc->ds_pebs_vaddr +
+ (index.wr << ARCH_PEBS_INDEX_WR_SHIFT));
+
+ index.wr = 0;
+ index.full = 0;
+ wrmsrq(MSR_IA32_PEBS_INDEX, index.whole);
+
+ mask = hybrid(cpuc->pmu, arch_pebs_cap).counters & cpuc->pebs_enabled;
+
+ if (!iregs)
+ iregs = &dummy_iregs;
+
+ /* Process all but the last event for each counter. */
+ for (at = base; at < top;) {
+ struct arch_pebs_header *header;
+ struct arch_pebs_basic *basic;
+ u64 pebs_status;
+
+ header = at;
+
+ if (WARN_ON_ONCE(!header->size))
+ break;
+
+ /* 1st fragment or single record must have basic group */
+ if (!header->basic) {
+ at += header->size;
+ continue;
+ }
+
+ basic = at + sizeof(struct arch_pebs_header);
+ pebs_status = mask & basic->applicable_counters;
+ __intel_pmu_handle_pebs_record(iregs, regs, data, at,
+ pebs_status, events, counts, last,
+ setup_arch_pebs_sample_data);
+
+ /* Skip non-last fragments */
+ while (arch_pebs_record_continued(header)) {
+ if (!header->size)
+ break;
+ at += header->size;
+ header = at;
+ }
+
+ /* Skip last fragment or the single record */
+ at += header->size;
+ }
+
+ __intel_pmu_handle_last_pebs_record(iregs, regs, data, mask, events,
+ counts, last,
+ setup_arch_pebs_sample_data);
+}
+
static void __init intel_arch_pebs_init(void)
{
/*
@@ -2786,6 +2967,7 @@ static void __init intel_arch_pebs_init(void)
*/
x86_pmu.arch_pebs = 1;
x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
+ x86_pmu.drain_pebs = intel_pmu_drain_arch_pebs;
x86_pmu.pebs_capable = ~0ULL;
x86_pmu.pebs_enable = __intel_pmu_pebs_enable;
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 9e1720d73244..fc7a4e7c718d 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -327,6 +327,12 @@
PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE | \
PERF_CAP_PEBS_TIMING_INFO)
+/* Arch PEBS */
+#define MSR_IA32_PEBS_BASE 0x000003f4
+#define MSR_IA32_PEBS_INDEX 0x000003f5
+#define ARCH_PEBS_OFFSET_MASK 0x7fffff
+#define ARCH_PEBS_INDEX_WR_SHIFT 4
+
#define MSR_IA32_RTIT_CTL 0x00000570
#define RTIT_CTL_TRACEEN BIT(0)
#define RTIT_CTL_CYCLEACC BIT(1)
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 0dfa06722bab..3b3848f0d339 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -437,6 +437,8 @@ static inline bool is_topdown_idx(int idx)
#define GLOBAL_STATUS_LBRS_FROZEN BIT_ULL(GLOBAL_STATUS_LBRS_FROZEN_BIT)
#define GLOBAL_STATUS_TRACE_TOPAPMI_BIT 55
#define GLOBAL_STATUS_TRACE_TOPAPMI BIT_ULL(GLOBAL_STATUS_TRACE_TOPAPMI_BIT)
+#define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT 54
+#define GLOBAL_STATUS_ARCH_PEBS_THRESHOLD BIT_ULL(GLOBAL_STATUS_ARCH_PEBS_THRESHOLD_BIT)
#define GLOBAL_STATUS_PERF_METRICS_OVF_BIT 48
#define GLOBAL_CTRL_EN_PERF_METRICS BIT_ULL(48)
@@ -507,6 +509,100 @@ struct pebs_cntr_header {
#define INTEL_CNTR_METRICS 0x3
+/*
+ * Arch PEBS
+ */
+union arch_pebs_index {
+ struct {
+ u64 rsvd:4,
+ wr:23,
+ rsvd2:4,
+ full:1,
+ en:1,
+ rsvd3:3,
+ thresh:23,
+ rsvd4:5;
+ };
+ u64 whole;
+};
+
+struct arch_pebs_header {
+ union {
+ u64 format;
+ struct {
+ u64 size:16, /* Record size */
+ rsvd:14,
+ mode:1, /* 64BIT_MODE */
+ cont:1,
+ rsvd2:3,
+ cntr:5,
+ lbr:2,
+ rsvd3:7,
+ xmm:1,
+ ymmh:1,
+ rsvd4:2,
+ opmask:1,
+ zmmh:1,
+ h16zmm:1,
+ rsvd5:5,
+ gpr:1,
+ aux:1,
+ basic:1;
+ };
+ };
+ u64 rsvd6;
+};
+
+struct arch_pebs_basic {
+ u64 ip;
+ u64 applicable_counters;
+ u64 tsc;
+ u64 retire :16, /* Retire Latency */
+ valid :1,
+ rsvd :47;
+ u64 rsvd2;
+ u64 rsvd3;
+};
+
+struct arch_pebs_aux {
+ u64 address;
+ u64 rsvd;
+ u64 rsvd2;
+ u64 rsvd3;
+ u64 rsvd4;
+ u64 aux;
+ u64 instr_latency :16,
+ pad2 :16,
+ cache_latency :16,
+ pad3 :16;
+ u64 tsx_tuning;
+};
+
+struct arch_pebs_gprs {
+ u64 flags, ip, ax, cx, dx, bx, sp, bp, si, di;
+ u64 r8, r9, r10, r11, r12, r13, r14, r15, ssp;
+ u64 rsvd;
+};
+
+struct arch_pebs_xer_header {
+ u64 xstate;
+ u64 rsvd;
+};
+
+#define ARCH_PEBS_LBR_NAN 0x0
+#define ARCH_PEBS_LBR_NUM_8 0x1
+#define ARCH_PEBS_LBR_NUM_16 0x2
+#define ARCH_PEBS_LBR_NUM_VAR 0x3
+#define ARCH_PEBS_BASE_LBR_ENTRIES 8
+struct arch_pebs_lbr_header {
+ u64 rsvd;
+ u64 ctl;
+ u64 depth;
+ u64 ler_from;
+ u64 ler_to;
+ u64 ler_info;
+};
+
/*
* AMD Extended Performance Monitoring and Debug cpuid feature detection
*/
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 09/12] perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (7 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 08/12] perf/x86/intel: Process arch-PEBS records or record fragments Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 10/12] perf/x86/intel: Update dyn_constranit base on PEBS event precise level Dapeng Mi
` (2 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi, Kan Liang
Arch-PEBS introduces a new MSR IA32_PEBS_BASE to store the arch-PEBS
buffer physical address. This patch allocates arch-PEBS buffer and then
initialize IA32_PEBS_BASE MSR with the buffer physical address.
Co-developed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 11 ++++-
arch/x86/events/intel/ds.c | 82 ++++++++++++++++++++++++++++-----
arch/x86/events/perf_event.h | 11 ++++-
arch/x86/include/asm/intel_ds.h | 3 +-
4 files changed, 92 insertions(+), 15 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index cab2ce73ad09..41c4af6bd62c 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5227,7 +5227,13 @@ int intel_cpuc_prepare(struct cpu_hw_events *cpuc, int cpu)
static int intel_pmu_cpu_prepare(int cpu)
{
- return intel_cpuc_prepare(&per_cpu(cpu_hw_events, cpu), cpu);
+ int ret;
+
+ ret = intel_cpuc_prepare(&per_cpu(cpu_hw_events, cpu), cpu);
+ if (ret)
+ return ret;
+
+ return alloc_arch_pebs_buf_on_cpu(cpu);
}
static void flip_smm_bit(void *data)
@@ -5457,6 +5463,7 @@ static void intel_pmu_cpu_starting(int cpu)
return;
init_debug_store_on_cpu(cpu);
+ init_arch_pebs_on_cpu(cpu);
/*
* Deal with CPUs that don't clear their LBRs on power-up, and that may
* even boot with LBRs enabled.
@@ -5554,6 +5561,7 @@ static void free_excl_cntrs(struct cpu_hw_events *cpuc)
static void intel_pmu_cpu_dying(int cpu)
{
fini_debug_store_on_cpu(cpu);
+ fini_arch_pebs_on_cpu(cpu);
}
void intel_cpuc_finish(struct cpu_hw_events *cpuc)
@@ -5574,6 +5582,7 @@ static void intel_pmu_cpu_dead(int cpu)
{
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
+ release_arch_pebs_buf_on_cpu(cpu);
intel_cpuc_finish(cpuc);
if (is_hybrid() && cpuc->pmu)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 651f3709c260..1ec54b0a5d3c 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -625,13 +625,18 @@ static int alloc_pebs_buffer(int cpu)
int max, node = cpu_to_node(cpu);
void *buffer, *insn_buff, *cea;
- if (!x86_pmu.ds_pebs)
+ if (!intel_pmu_has_pebs())
return 0;
buffer = dsalloc_pages(bsiz, GFP_KERNEL, cpu);
if (unlikely(!buffer))
return -ENOMEM;
+ if (x86_pmu.arch_pebs) {
+ hwev->pebs_vaddr = buffer;
+ return 0;
+ }
+
/*
* HSW+ already provides us the eventing ip; no need to allocate this
* buffer then.
@@ -644,7 +649,7 @@ static int alloc_pebs_buffer(int cpu)
}
per_cpu(insn_buffer, cpu) = insn_buff;
}
- hwev->ds_pebs_vaddr = buffer;
+ hwev->pebs_vaddr = buffer;
/* Update the cpu entry area mapping */
cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
ds->pebs_buffer_base = (unsigned long) cea;
@@ -660,17 +665,20 @@ static void release_pebs_buffer(int cpu)
struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
void *cea;
- if (!x86_pmu.ds_pebs)
+ if (!intel_pmu_has_pebs())
return;
- kfree(per_cpu(insn_buffer, cpu));
- per_cpu(insn_buffer, cpu) = NULL;
+ if (x86_pmu.ds_pebs) {
+ kfree(per_cpu(insn_buffer, cpu));
+ per_cpu(insn_buffer, cpu) = NULL;
- /* Clear the fixmap */
- cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
- ds_clear_cea(cea, x86_pmu.pebs_buffer_size);
- dsfree_pages(hwev->ds_pebs_vaddr, x86_pmu.pebs_buffer_size);
- hwev->ds_pebs_vaddr = NULL;
+ /* Clear the fixmap */
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
+ ds_clear_cea(cea, x86_pmu.pebs_buffer_size);
+ }
+
+ dsfree_pages(hwev->pebs_vaddr, x86_pmu.pebs_buffer_size);
+ hwev->pebs_vaddr = NULL;
}
static int alloc_bts_buffer(int cpu)
@@ -823,6 +831,56 @@ void reserve_ds_buffers(void)
}
}
+inline int alloc_arch_pebs_buf_on_cpu(int cpu)
+{
+ if (!x86_pmu.arch_pebs)
+ return 0;
+
+ return alloc_pebs_buffer(cpu);
+}
+
+inline void release_arch_pebs_buf_on_cpu(int cpu)
+{
+ if (!x86_pmu.arch_pebs)
+ return;
+
+ release_pebs_buffer(cpu);
+}
+
+void init_arch_pebs_on_cpu(int cpu)
+{
+ struct cpu_hw_events *cpuc = per_cpu_ptr(&cpu_hw_events, cpu);
+ u64 arch_pebs_base;
+
+ if (!x86_pmu.arch_pebs)
+ return;
+
+ if (!cpuc->pebs_vaddr) {
+ WARN(1, "Fail to allocate PEBS buffer on CPU %d\n", cpu);
+ x86_pmu.pebs_active = 0;
+ return;
+ }
+
+ /*
+ * 4KB-aligned pointer of the output buffer
+ * (__alloc_pages_node() return page aligned address)
+ * Buffer Size = 4KB * 2^SIZE
+ * contiguous physical buffer (__alloc_pages_node() with order)
+ */
+ arch_pebs_base = virt_to_phys(cpuc->pebs_vaddr) | PEBS_BUFFER_SHIFT;
+ wrmsr_on_cpu(cpu, MSR_IA32_PEBS_BASE, (u32)arch_pebs_base,
+ (u32)(arch_pebs_base >> 32));
+ x86_pmu.pebs_active = 1;
+}
+
+inline void fini_arch_pebs_on_cpu(int cpu)
+{
+ if (!x86_pmu.arch_pebs)
+ return;
+
+ wrmsr_on_cpu(cpu, MSR_IA32_PEBS_BASE, 0, 0);
+}
+
/*
* BTS
*/
@@ -2905,8 +2963,8 @@ static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
return;
}
- base = cpuc->ds_pebs_vaddr;
- top = (void *)((u64)cpuc->ds_pebs_vaddr +
+ base = cpuc->pebs_vaddr;
+ top = (void *)((u64)cpuc->pebs_vaddr +
(index.wr << ARCH_PEBS_INDEX_WR_SHIFT));
index.wr = 0;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index ca5289980b52..13f411bca6bc 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -283,8 +283,9 @@ struct cpu_hw_events {
* Intel DebugStore bits
*/
struct debug_store *ds;
- void *ds_pebs_vaddr;
void *ds_bts_vaddr;
+ /* DS based PEBS or arch-PEBS buffer address */
+ void *pebs_vaddr;
u64 pebs_enabled;
int n_pebs;
int n_large_pebs;
@@ -1617,6 +1618,14 @@ extern void intel_cpuc_finish(struct cpu_hw_events *cpuc);
int intel_pmu_init(void);
+int alloc_arch_pebs_buf_on_cpu(int cpu);
+
+void release_arch_pebs_buf_on_cpu(int cpu);
+
+void init_arch_pebs_on_cpu(int cpu);
+
+void fini_arch_pebs_on_cpu(int cpu);
+
void init_debug_store_on_cpu(int cpu);
void fini_debug_store_on_cpu(int cpu);
diff --git a/arch/x86/include/asm/intel_ds.h b/arch/x86/include/asm/intel_ds.h
index 5dbeac48a5b9..023c2883f9f3 100644
--- a/arch/x86/include/asm/intel_ds.h
+++ b/arch/x86/include/asm/intel_ds.h
@@ -4,7 +4,8 @@
#include <linux/percpu-defs.h>
#define BTS_BUFFER_SIZE (PAGE_SIZE << 4)
-#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4)
+#define PEBS_BUFFER_SHIFT 4
+#define PEBS_BUFFER_SIZE (PAGE_SIZE << PEBS_BUFFER_SHIFT)
/* The maximal number of PEBS events: */
#define MAX_PEBS_EVENTS_FMT4 8
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 10/12] perf/x86/intel: Update dyn_constranit base on PEBS event precise level
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (8 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 09/12] perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 11/12] perf/x86/intel: Setup PEBS data configuration and enable legacy groups Dapeng Mi
2025-10-15 6:44 ` [Patch v8 12/12] perf/x86/intel: Add counter group support for arch-PEBS Dapeng Mi
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
arch-PEBS provides CPUIDs to enumerate which counters support PEBS
sampling and precise distribution PEBS sampling. Thus PEBS constraints
should be dynamically configured base on these counter and precise
distribution bitmap instead of defining them statically.
Update event dyn_constraint base on PEBS event precise level.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 11 +++++++++++
arch/x86/events/intel/ds.c | 1 +
2 files changed, 12 insertions(+)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 41c4af6bd62c..818c197585c6 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4252,6 +4252,8 @@ static int intel_pmu_hw_config(struct perf_event *event)
}
if (event->attr.precise_ip) {
+ struct arch_pebs_cap pebs_cap = hybrid(event->pmu, arch_pebs_cap);
+
if ((event->attr.config & INTEL_ARCH_EVENT_MASK) == INTEL_FIXED_VLBR_EVENT)
return -EINVAL;
@@ -4265,6 +4267,15 @@ static int intel_pmu_hw_config(struct perf_event *event)
}
if (x86_pmu.pebs_aliases)
x86_pmu.pebs_aliases(event);
+
+ if (x86_pmu.arch_pebs) {
+ u64 cntr_mask = hybrid(event->pmu, intel_ctrl) &
+ ~GLOBAL_CTRL_EN_PERF_METRICS;
+ u64 pebs_mask = event->attr.precise_ip >= 3 ?
+ pebs_cap.pdists : pebs_cap.counters;
+ if (cntr_mask != pebs_mask)
+ event->hw.dyn_constraint &= pebs_mask;
+ }
}
if (needs_branch_stack(event)) {
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 1ec54b0a5d3c..759eff6aa83e 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -3027,6 +3027,7 @@ static void __init intel_arch_pebs_init(void)
x86_pmu.pebs_buffer_size = PEBS_BUFFER_SIZE;
x86_pmu.drain_pebs = intel_pmu_drain_arch_pebs;
x86_pmu.pebs_capable = ~0ULL;
+ x86_pmu.flags |= PMU_FL_PEBS_ALL;
x86_pmu.pebs_enable = __intel_pmu_pebs_enable;
x86_pmu.pebs_disable = __intel_pmu_pebs_disable;
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 11/12] perf/x86/intel: Setup PEBS data configuration and enable legacy groups
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (9 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 10/12] perf/x86/intel: Update dyn_constranit base on PEBS event precise level Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
2025-10-15 6:44 ` [Patch v8 12/12] perf/x86/intel: Add counter group support for arch-PEBS Dapeng Mi
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi, Kan Liang
Different with legacy PEBS, arch-PEBS provides per-counter PEBS data
configuration by programing MSR IA32_PMC_GPx/FXx_CFG_C MSRs.
This patch obtains PEBS data configuration from event attribute and then
writes the PEBS data configuration to MSR IA32_PMC_GPx/FXx_CFG_C and
enable corresponding PEBS groups.
Please notice this patch only enables XMM SIMD regs sampling for
arch-PEBS, the other SIMD regs (OPMASK/YMM/ZMM) sampling on arch-PEBS
would be supported after PMI based SIMD regs (OPMASK/YMM/ZMM) sampling
is supported.
Co-developed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 136 ++++++++++++++++++++++++++++++-
arch/x86/events/intel/ds.c | 17 ++++
arch/x86/events/perf_event.h | 4 +
arch/x86/include/asm/intel_ds.h | 7 ++
arch/x86/include/asm/msr-index.h | 8 ++
5 files changed, 171 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 818c197585c6..c8cd490aa539 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2563,6 +2563,45 @@ static void intel_pmu_disable_fixed(struct perf_event *event)
cpuc->fixed_ctrl_val &= ~mask;
}
+static inline void __intel_pmu_update_event_ext(int idx, u64 ext)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ u32 msr;
+
+ if (idx < INTEL_PMC_IDX_FIXED) {
+ msr = MSR_IA32_PMC_V6_GP0_CFG_C +
+ x86_pmu.addr_offset(idx, false);
+ } else {
+ msr = MSR_IA32_PMC_V6_FX0_CFG_C +
+ x86_pmu.addr_offset(idx - INTEL_PMC_IDX_FIXED, false);
+ }
+
+ cpuc->cfg_c_val[idx] = ext;
+ wrmsrq(msr, ext);
+}
+
+static void intel_pmu_disable_event_ext(struct perf_event *event)
+{
+ if (!x86_pmu.arch_pebs)
+ return;
+
+ /*
+ * Only clear CFG_C MSR for PEBS counter group events,
+ * it avoids the HW counter's value to be added into
+ * other PEBS records incorrectly after PEBS counter
+ * group events are disabled.
+ *
+ * For other events, it's unnecessary to clear CFG_C MSRs
+ * since CFG_C doesn't take effect if counter is in
+ * disabled state. That helps to reduce the WRMSR overhead
+ * in context switches.
+ */
+ if (!is_pebs_counter_event_group(event))
+ return;
+
+ __intel_pmu_update_event_ext(event->hw.idx, 0);
+}
+
static void intel_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
@@ -2571,9 +2610,12 @@ static void intel_pmu_disable_event(struct perf_event *event)
switch (idx) {
case 0 ... INTEL_PMC_IDX_FIXED - 1:
intel_clear_masks(event, idx);
+ intel_pmu_disable_event_ext(event);
x86_pmu_disable_event(event);
break;
case INTEL_PMC_IDX_FIXED ... INTEL_PMC_IDX_FIXED_BTS - 1:
+ intel_pmu_disable_event_ext(event);
+ fallthrough;
case INTEL_PMC_IDX_METRIC_BASE ... INTEL_PMC_IDX_METRIC_END:
intel_pmu_disable_fixed(event);
break;
@@ -2940,6 +2982,66 @@ static void intel_pmu_enable_acr(struct perf_event *event)
DEFINE_STATIC_CALL_NULL(intel_pmu_enable_acr_event, intel_pmu_enable_acr);
+static void intel_pmu_enable_event_ext(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ union arch_pebs_index old, new;
+ struct arch_pebs_cap cap;
+ u64 ext = 0;
+
+ if (!x86_pmu.arch_pebs)
+ return;
+
+ cap = hybrid(cpuc->pmu, arch_pebs_cap);
+
+ if (event->attr.precise_ip) {
+ u64 pebs_data_cfg = intel_get_arch_pebs_data_config(event);
+
+ ext |= ARCH_PEBS_EN;
+ if (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD)
+ ext |= (-hwc->sample_period) & ARCH_PEBS_RELOAD;
+
+ if (pebs_data_cfg && cap.caps) {
+ if (pebs_data_cfg & PEBS_DATACFG_MEMINFO)
+ ext |= ARCH_PEBS_AUX & cap.caps;
+
+ if (pebs_data_cfg & PEBS_DATACFG_GP)
+ ext |= ARCH_PEBS_GPR & cap.caps;
+
+ if (pebs_data_cfg & PEBS_DATACFG_XMMS)
+ ext |= ARCH_PEBS_VECR_XMM & cap.caps;
+
+ if (pebs_data_cfg & PEBS_DATACFG_LBRS)
+ ext |= ARCH_PEBS_LBR & cap.caps;
+ }
+
+ if (cpuc->n_pebs == cpuc->n_large_pebs)
+ new.thresh = ARCH_PEBS_THRESH_MULTI;
+ else
+ new.thresh = ARCH_PEBS_THRESH_SINGLE;
+
+ rdmsrq(MSR_IA32_PEBS_INDEX, old.whole);
+ if (new.thresh != old.thresh || !old.en) {
+ if (old.thresh == ARCH_PEBS_THRESH_MULTI && old.wr > 0) {
+ /*
+ * Large PEBS was enabled.
+ * Drain PEBS buffer before applying the single PEBS.
+ */
+ intel_pmu_drain_pebs_buffer();
+ } else {
+ new.wr = 0;
+ new.full = 0;
+ new.en = 1;
+ wrmsrq(MSR_IA32_PEBS_INDEX, new.whole);
+ }
+ }
+ }
+
+ if (cpuc->cfg_c_val[hwc->idx] != ext)
+ __intel_pmu_update_event_ext(hwc->idx, ext);
+}
+
static void intel_pmu_enable_event(struct perf_event *event)
{
u64 enable_mask = ARCH_PERFMON_EVENTSEL_ENABLE;
@@ -2955,10 +3057,12 @@ static void intel_pmu_enable_event(struct perf_event *event)
enable_mask |= ARCH_PERFMON_EVENTSEL_BR_CNTR;
intel_set_masks(event, idx);
static_call_cond(intel_pmu_enable_acr_event)(event);
+ intel_pmu_enable_event_ext(event);
__x86_pmu_enable_event(hwc, enable_mask);
break;
case INTEL_PMC_IDX_FIXED ... INTEL_PMC_IDX_FIXED_BTS - 1:
static_call_cond(intel_pmu_enable_acr_event)(event);
+ intel_pmu_enable_event_ext(event);
fallthrough;
case INTEL_PMC_IDX_METRIC_BASE ... INTEL_PMC_IDX_METRIC_END:
intel_pmu_enable_fixed(event);
@@ -5301,6 +5405,30 @@ static inline bool intel_pmu_broken_perf_cap(void)
return false;
}
+static inline void __intel_update_pmu_caps(struct pmu *pmu)
+{
+ struct pmu *dest_pmu = pmu ? pmu : x86_get_pmu(smp_processor_id());
+
+ if (hybrid(pmu, arch_pebs_cap).caps & ARCH_PEBS_VECR_XMM)
+ dest_pmu->capabilities |= PERF_PMU_CAP_EXTENDED_REGS;
+}
+
+static inline void __intel_update_large_pebs_flags(struct pmu *pmu)
+{
+ u64 caps = hybrid(pmu, arch_pebs_cap).caps;
+
+ x86_pmu.large_pebs_flags |= PERF_SAMPLE_TIME;
+ if (caps & ARCH_PEBS_LBR)
+ x86_pmu.large_pebs_flags |= PERF_SAMPLE_BRANCH_STACK;
+
+ if (!(caps & ARCH_PEBS_AUX))
+ x86_pmu.large_pebs_flags &= ~PERF_SAMPLE_DATA_SRC;
+ if (!(caps & ARCH_PEBS_GPR)) {
+ x86_pmu.large_pebs_flags &=
+ ~(PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER);
+ }
+}
+
static void update_pmu_cap(struct pmu *pmu)
{
unsigned int eax, ebx, ecx, edx;
@@ -5348,8 +5476,12 @@ static void update_pmu_cap(struct pmu *pmu)
hybrid(pmu, arch_pebs_cap).counters = pebs_mask;
hybrid(pmu, arch_pebs_cap).pdists = pdists_mask;
- if (WARN_ON((pebs_mask | pdists_mask) & ~cntrs_mask))
+ if (WARN_ON((pebs_mask | pdists_mask) & ~cntrs_mask)) {
x86_pmu.arch_pebs = 0;
+ } else {
+ __intel_update_pmu_caps(pmu);
+ __intel_update_large_pebs_flags(pmu);
+ }
} else {
WARN_ON(x86_pmu.arch_pebs == 1);
x86_pmu.arch_pebs = 0;
@@ -5513,6 +5645,8 @@ static void intel_pmu_cpu_starting(int cpu)
}
}
+ __intel_update_pmu_caps(cpuc->pmu);
+
if (!cpuc->shared_regs)
return;
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 759eff6aa83e..becdc9a53d10 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1528,6 +1528,18 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc,
}
}
+u64 intel_get_arch_pebs_data_config(struct perf_event *event)
+{
+ u64 pebs_data_cfg = 0;
+
+ if (WARN_ON(event->hw.idx < 0 || event->hw.idx >= X86_PMC_IDX_MAX))
+ return 0;
+
+ pebs_data_cfg |= pebs_update_adaptive_cfg(event);
+
+ return pebs_data_cfg;
+}
+
void intel_pmu_pebs_add(struct perf_event *event)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -2969,6 +2981,11 @@ static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
index.wr = 0;
index.full = 0;
+ index.en = 1;
+ if (cpuc->n_pebs == cpuc->n_large_pebs)
+ index.thresh = ARCH_PEBS_THRESH_MULTI;
+ else
+ index.thresh = ARCH_PEBS_THRESH_SINGLE;
wrmsrq(MSR_IA32_PEBS_INDEX, index.whole);
mask = hybrid(cpuc->pmu, arch_pebs_cap).counters & cpuc->pebs_enabled;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 13f411bca6bc..3161ec0a3416 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -304,6 +304,8 @@ struct cpu_hw_events {
/* Intel ACR configuration */
u64 acr_cfg_b[X86_PMC_IDX_MAX];
u64 acr_cfg_c[X86_PMC_IDX_MAX];
+ /* Cached CFG_C values */
+ u64 cfg_c_val[X86_PMC_IDX_MAX];
/*
* Intel LBR bits
@@ -1782,6 +1784,8 @@ void intel_pmu_pebs_data_source_cmt(void);
void intel_pmu_pebs_data_source_lnl(void);
+u64 intel_get_arch_pebs_data_config(struct perf_event *event);
+
int intel_pmu_setup_lbr_filter(struct perf_event *event);
void intel_pt_interrupt(void);
diff --git a/arch/x86/include/asm/intel_ds.h b/arch/x86/include/asm/intel_ds.h
index 023c2883f9f3..695f87efbeb8 100644
--- a/arch/x86/include/asm/intel_ds.h
+++ b/arch/x86/include/asm/intel_ds.h
@@ -7,6 +7,13 @@
#define PEBS_BUFFER_SHIFT 4
#define PEBS_BUFFER_SIZE (PAGE_SIZE << PEBS_BUFFER_SHIFT)
+/*
+ * The largest PEBS record could consume a page, ensure
+ * a record at least can be written after triggering PMI.
+ */
+#define ARCH_PEBS_THRESH_MULTI ((PEBS_BUFFER_SIZE - PAGE_SIZE) >> PEBS_BUFFER_SHIFT)
+#define ARCH_PEBS_THRESH_SINGLE 1
+
/* The maximal number of PEBS events: */
#define MAX_PEBS_EVENTS_FMT4 8
#define MAX_PEBS_EVENTS 32
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index fc7a4e7c718d..f1ef9ac38bfb 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -333,6 +333,14 @@
#define ARCH_PEBS_OFFSET_MASK 0x7fffff
#define ARCH_PEBS_INDEX_WR_SHIFT 4
+#define ARCH_PEBS_RELOAD 0xffffffff
+#define ARCH_PEBS_LBR_SHIFT 40
+#define ARCH_PEBS_LBR (0x3ull << ARCH_PEBS_LBR_SHIFT)
+#define ARCH_PEBS_VECR_XMM BIT_ULL(49)
+#define ARCH_PEBS_GPR BIT_ULL(61)
+#define ARCH_PEBS_AUX BIT_ULL(62)
+#define ARCH_PEBS_EN BIT_ULL(63)
+
#define MSR_IA32_RTIT_CTL 0x00000570
#define RTIT_CTL_TRACEEN BIT(0)
#define RTIT_CTL_CYCLEACC BIT(1)
--
2.34.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [Patch v8 12/12] perf/x86/intel: Add counter group support for arch-PEBS
2025-10-15 6:44 [Patch v8 00/12] arch-PEBS enabling for Intel platforms Dapeng Mi
` (10 preceding siblings ...)
2025-10-15 6:44 ` [Patch v8 11/12] perf/x86/intel: Setup PEBS data configuration and enable legacy groups Dapeng Mi
@ 2025-10-15 6:44 ` Dapeng Mi
11 siblings, 0 replies; 22+ messages in thread
From: Dapeng Mi @ 2025-10-15 6:44 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Ian Rogers, Adrian Hunter, Alexander Shishkin,
Andi Kleen, Eranian Stephane
Cc: linux-kernel, linux-perf-users, Dapeng Mi, Dapeng Mi
Base on previous adaptive PEBS counter snapshot support, add counter
group support for architectural PEBS. Since arch-PEBS shares same
counter group layout with adaptive PEBS, directly reuse
__setup_pebs_counter_group() helper to process arch-PEBS counter group.
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
arch/x86/events/intel/core.c | 38 ++++++++++++++++++++++++++++---
arch/x86/events/intel/ds.c | 29 ++++++++++++++++++++---
arch/x86/include/asm/msr-index.h | 6 +++++
arch/x86/include/asm/perf_event.h | 13 ++++++++---
4 files changed, 77 insertions(+), 9 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index c8cd490aa539..52bf3b4bc938 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3014,6 +3014,17 @@ static void intel_pmu_enable_event_ext(struct perf_event *event)
if (pebs_data_cfg & PEBS_DATACFG_LBRS)
ext |= ARCH_PEBS_LBR & cap.caps;
+
+ if (pebs_data_cfg &
+ (PEBS_DATACFG_CNTR_MASK << PEBS_DATACFG_CNTR_SHIFT))
+ ext |= ARCH_PEBS_CNTR_GP & cap.caps;
+
+ if (pebs_data_cfg &
+ (PEBS_DATACFG_FIX_MASK << PEBS_DATACFG_FIX_SHIFT))
+ ext |= ARCH_PEBS_CNTR_FIXED & cap.caps;
+
+ if (pebs_data_cfg & PEBS_DATACFG_METRICS)
+ ext |= ARCH_PEBS_CNTR_METRICS & cap.caps;
}
if (cpuc->n_pebs == cpuc->n_large_pebs)
@@ -3038,6 +3049,9 @@ static void intel_pmu_enable_event_ext(struct perf_event *event)
}
}
+ if (is_pebs_counter_event_group(event))
+ ext |= ARCH_PEBS_CNTR_ALLOW;
+
if (cpuc->cfg_c_val[hwc->idx] != ext)
__intel_pmu_update_event_ext(hwc->idx, ext);
}
@@ -4323,6 +4337,20 @@ static bool intel_pmu_is_acr_group(struct perf_event *event)
return false;
}
+static inline bool intel_pmu_has_pebs_counter_group(struct pmu *pmu)
+{
+ u64 caps;
+
+ if (x86_pmu.intel_cap.pebs_format >= 6 && x86_pmu.intel_cap.pebs_baseline)
+ return true;
+
+ caps = hybrid(pmu, arch_pebs_cap).caps;
+ if (x86_pmu.arch_pebs && (caps & ARCH_PEBS_CNTR_MASK))
+ return true;
+
+ return false;
+}
+
static inline void intel_pmu_set_acr_cntr_constr(struct perf_event *event,
u64 *cause_mask, int *num)
{
@@ -4471,8 +4499,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
}
if ((event->attr.sample_type & PERF_SAMPLE_READ) &&
- (x86_pmu.intel_cap.pebs_format >= 6) &&
- x86_pmu.intel_cap.pebs_baseline &&
+ intel_pmu_has_pebs_counter_group(event->pmu) &&
is_sampling_event(event) &&
event->attr.precise_ip)
event->group_leader->hw.flags |= PERF_X86_EVENT_PEBS_CNTR;
@@ -5420,6 +5447,8 @@ static inline void __intel_update_large_pebs_flags(struct pmu *pmu)
x86_pmu.large_pebs_flags |= PERF_SAMPLE_TIME;
if (caps & ARCH_PEBS_LBR)
x86_pmu.large_pebs_flags |= PERF_SAMPLE_BRANCH_STACK;
+ if (caps & ARCH_PEBS_CNTR_MASK)
+ x86_pmu.large_pebs_flags |= PERF_SAMPLE_READ;
if (!(caps & ARCH_PEBS_AUX))
x86_pmu.large_pebs_flags &= ~PERF_SAMPLE_DATA_SRC;
@@ -7133,8 +7162,11 @@ __init int intel_pmu_init(void)
* Many features on and after V6 require dynamic constraint,
* e.g., Arch PEBS, ACR.
*/
- if (version >= 6)
+ if (version >= 6) {
x86_pmu.flags |= PMU_FL_DYN_CONSTRAINT;
+ x86_pmu.late_setup = intel_pmu_late_setup;
+ }
+
/*
* Install the hw-cache-events table:
*/
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index becdc9a53d10..3dedf7a0acf6 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1530,13 +1530,20 @@ pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc,
u64 intel_get_arch_pebs_data_config(struct perf_event *event)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
u64 pebs_data_cfg = 0;
+ u64 cntr_mask;
if (WARN_ON(event->hw.idx < 0 || event->hw.idx >= X86_PMC_IDX_MAX))
return 0;
pebs_data_cfg |= pebs_update_adaptive_cfg(event);
+ cntr_mask = (PEBS_DATACFG_CNTR_MASK << PEBS_DATACFG_CNTR_SHIFT) |
+ (PEBS_DATACFG_FIX_MASK << PEBS_DATACFG_FIX_SHIFT) |
+ PEBS_DATACFG_CNTR | PEBS_DATACFG_METRICS;
+ pebs_data_cfg |= cpuc->pebs_data_cfg & cntr_mask;
+
return pebs_data_cfg;
}
@@ -2441,6 +2448,24 @@ static void setup_arch_pebs_sample_data(struct perf_event *event,
}
}
+ if (header->cntr) {
+ struct arch_pebs_cntr_header *cntr = next_record;
+ unsigned int nr;
+
+ next_record += sizeof(struct arch_pebs_cntr_header);
+
+ if (is_pebs_counter_event_group(event)) {
+ __setup_pebs_counter_group(cpuc, event,
+ (struct pebs_cntr_header *)cntr, next_record);
+ data->sample_flags |= PERF_SAMPLE_READ;
+ }
+
+ nr = hweight32(cntr->cntr) + hweight32(cntr->fixed);
+ if (cntr->metrics == INTEL_CNTR_METRICS)
+ nr += 2;
+ next_record += nr * sizeof(u64);
+ }
+
/* Parse followed fragments if there are. */
if (arch_pebs_record_continued(header)) {
at = at + header->size;
@@ -3116,10 +3141,8 @@ static void __init intel_ds_pebs_init(void)
break;
case 6:
- if (x86_pmu.intel_cap.pebs_baseline) {
+ if (x86_pmu.intel_cap.pebs_baseline)
x86_pmu.large_pebs_flags |= PERF_SAMPLE_READ;
- x86_pmu.late_setup = intel_pmu_late_setup;
- }
fallthrough;
case 5:
x86_pmu.pebs_ept = 1;
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index f1ef9ac38bfb..65cc528fbad8 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -334,12 +334,18 @@
#define ARCH_PEBS_INDEX_WR_SHIFT 4
#define ARCH_PEBS_RELOAD 0xffffffff
+#define ARCH_PEBS_CNTR_ALLOW BIT_ULL(35)
+#define ARCH_PEBS_CNTR_GP BIT_ULL(36)
+#define ARCH_PEBS_CNTR_FIXED BIT_ULL(37)
+#define ARCH_PEBS_CNTR_METRICS BIT_ULL(38)
#define ARCH_PEBS_LBR_SHIFT 40
#define ARCH_PEBS_LBR (0x3ull << ARCH_PEBS_LBR_SHIFT)
#define ARCH_PEBS_VECR_XMM BIT_ULL(49)
#define ARCH_PEBS_GPR BIT_ULL(61)
#define ARCH_PEBS_AUX BIT_ULL(62)
#define ARCH_PEBS_EN BIT_ULL(63)
+#define ARCH_PEBS_CNTR_MASK (ARCH_PEBS_CNTR_GP | ARCH_PEBS_CNTR_FIXED | \
+ ARCH_PEBS_CNTR_METRICS)
#define MSR_IA32_RTIT_CTL 0x00000570
#define RTIT_CTL_TRACEEN BIT(0)
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 3b3848f0d339..7276ba70c88a 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -141,16 +141,16 @@
#define ARCH_PERFMON_EVENTS_COUNT 7
#define PEBS_DATACFG_MEMINFO BIT_ULL(0)
-#define PEBS_DATACFG_GP BIT_ULL(1)
+#define PEBS_DATACFG_GP BIT_ULL(1)
#define PEBS_DATACFG_XMMS BIT_ULL(2)
#define PEBS_DATACFG_LBRS BIT_ULL(3)
-#define PEBS_DATACFG_LBR_SHIFT 24
#define PEBS_DATACFG_CNTR BIT_ULL(4)
+#define PEBS_DATACFG_METRICS BIT_ULL(5)
+#define PEBS_DATACFG_LBR_SHIFT 24
#define PEBS_DATACFG_CNTR_SHIFT 32
#define PEBS_DATACFG_CNTR_MASK GENMASK_ULL(15, 0)
#define PEBS_DATACFG_FIX_SHIFT 48
#define PEBS_DATACFG_FIX_MASK GENMASK_ULL(7, 0)
-#define PEBS_DATACFG_METRICS BIT_ULL(5)
/* Steal the highest bit of pebs_data_cfg for SW usage */
#define PEBS_UPDATE_DS_SW BIT_ULL(63)
@@ -603,6 +603,13 @@ struct arch_pebs_lbr_header {
u64 ler_info;
};
+struct arch_pebs_cntr_header {
+ u32 cntr;
+ u32 fixed;
+ u32 metrics;
+ u32 reserved;
+};
+
/*
* AMD Extended Performance Monitoring and Debug cpuid feature detection
*/
--
2.34.1
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