[PATCH v11 02/11] perf/x86/core: Refactor hw->idx checks and cleanup

Like Xu
2020-05-14T08:32:13Z

For intel_pmu_en/disable_event(), reorder the branches checks for
hw->idx and make them sorted by probability: gp,fixed,bts,others.

Clean up the x86_assign_hw_event() by converting multiple if-else
statements to a switch statement.

To skip x86_perf_event_update() and x86_perf_event_set_period(),
it's generic to replace "idx == INTEL_PMC_IDX_FIXED_BTS" check with
'!hwc->event_base' because that should be 0 for all non-gp/fixed cases.

Wrap related bit operations into intel_set/clear_masks() and
make the main path more cleaner and readable.

No functional changes.

Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Original-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
arch/x86/events/core.c | 25 +++++++----
arch/x86/events/intel/core.c | 85 +++++++++++++++++++-----------------
2 files changed, 62 insertions(+), 48 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index a619763e96e1..f7a259dcbb06 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -71,10 +71,9 @@ u64 x86_perf_event_update(struct perf_event *event)
struct hw_perf_event *hwc = &event->hw;
int shift = 64 - x86_pmu.cntval_bits;
u64 prev_raw_count, new_raw_count;
- int idx = hwc->idx;
u64 delta;

- if (idx == INTEL_PMC_IDX_FIXED_BTS)
+ if (unlikely(!hwc->event_base))
return 0;

/*
@@ -1097,22 +1096,30 @@ static inline void x86_assign_hw_event(struct perf_event *event,
struct cpu_hw_events *cpuc, int i)
{
struct hw_perf_event *hwc = &event->hw;
+ int idx;

- hwc->idx = cpuc->assign[i];
+ idx = hwc->idx = cpuc->assign[i];
hwc->last_cpu = smp_processor_id();
hwc->last_tag = ++cpuc->tags[i];

- if (hwc->idx == INTEL_PMC_IDX_FIXED_BTS) {
+ switch (hwc->idx) {
+ case INTEL_PMC_IDX_FIXED_BTS:
hwc->config_base = 0;
hwc->event_base = 0;
- } else if (hwc->idx >= INTEL_PMC_IDX_FIXED) {
+ break;
+
+ case INTEL_PMC_IDX_FIXED ... INTEL_PMC_IDX_FIXED_BTS-1:
hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
- hwc->event_base = MSR_ARCH_PERFMON_FIXED_CTR0 + (hwc->idx - INTEL_PMC_IDX_FIXED);
- hwc->event_base_rdpmc = (hwc->idx - INTEL_PMC_IDX_FIXED) | 1<<30;
- } else {
+ hwc->event_base = MSR_ARCH_PERFMON_FIXED_CTR0 +
+ (idx - INTEL_PMC_IDX_FIXED);
+ hwc->event_base_rdpmc = (idx - INTEL_PMC_IDX_FIXED) | 1<<30;
+ break;
+
+ default:
hwc->config_base = x86_pmu_config_addr(hwc->idx);
hwc->event_base = x86_pmu_event_addr(hwc->idx);
hwc->event_base_rdpmc = x86_pmu_rdpmc_index(hwc->idx);
+ break;
}
}

@@ -1233,7 +1240,7 @@ int x86_perf_event_set_period(struct perf_event *event)
s64 period = hwc->sample_period;
int ret = 0, idx = hwc->idx;

- if (idx == INTEL_PMC_IDX_FIXED_BTS)
+ if (unlikely(!hwc->event_base))
return 0;

/*
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 332954cccece..f1439acbf7e6 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2136,8 +2136,35 @@ static inline void intel_pmu_ack_status(u64 ack)
wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);
}

-static void intel_pmu_disable_fixed(struct hw_perf_event *hwc)
+static inline bool event_is_checkpointed(struct perf_event *event)
+{
+ return unlikely(event->hw.config & HSW_IN_TX_CHECKPOINTED) != 0;
+}
+
+static inline void intel_set_masks(struct perf_event *event, int idx)
+{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+ if (event->attr.exclude_host)
+ __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_guest_mask);
+ if (event->attr.exclude_guest)
+ __set_bit(idx, (unsigned long *)&cpuc->intel_ctrl_host_mask);
+ if (event_is_checkpointed(event))
+ __set_bit(idx, (unsigned long *)&cpuc->intel_cp_status);
+}
+
+static inline void intel_clear_masks(struct perf_event *event, int idx)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+ __clear_bit(idx, (unsigned long *)&cpuc->intel_ctrl_guest_mask);
+ __clear_bit(idx, (unsigned long *)&cpuc->intel_ctrl_host_mask);
+ __clear_bit(idx, (unsigned long *)&cpuc->intel_cp_status);
+}
+
+static void intel_pmu_disable_fixed(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx - INTEL_PMC_IDX_FIXED;
u64 ctrl_val, mask;

@@ -2148,31 +2175,22 @@ static void intel_pmu_disable_fixed(struct hw_perf_event *hwc)
wrmsrl(hwc->config_base, ctrl_val);
}

-static inline bool event_is_checkpointed(struct perf_event *event)
-{
- return (event->hw.config & HSW_IN_TX_CHECKPOINTED) != 0;
-}
-
static void intel_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
- struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ int idx = hwc->idx;

- if (unlikely(hwc->idx == INTEL_PMC_IDX_FIXED_BTS)) {
+ if (idx < INTEL_PMC_IDX_FIXED) {
+ intel_clear_masks(event, idx);
+ x86_pmu_disable_event(event);
+ } else if (idx < INTEL_PMC_IDX_FIXED_BTS) {
+ intel_clear_masks(event, idx);
+ intel_pmu_disable_fixed(event);
+ } else if (idx == INTEL_PMC_IDX_FIXED_BTS) {
intel_pmu_disable_bts();
intel_pmu_drain_bts_buffer();
- return;
}

- cpuc->intel_ctrl_guest_mask &= ~(1ull << hwc->idx);
- cpuc->intel_ctrl_host_mask &= ~(1ull << hwc->idx);
- cpuc->intel_cp_status &= ~(1ull << hwc->idx);
-
- if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL))
- intel_pmu_disable_fixed(hwc);
- else
- x86_pmu_disable_event(event);
-
/*
* Needs to be called after x86_pmu_disable_event,
* so we don't trigger the event without PEBS bit set.
@@ -2238,33 +2256,22 @@ static void intel_pmu_enable_fixed(struct perf_event *event)
static void intel_pmu_enable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
- struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
-
- if (unlikely(hwc->idx == INTEL_PMC_IDX_FIXED_BTS)) {
- if (!__this_cpu_read(cpu_hw_events.enabled))
- return;
-
- intel_pmu_enable_bts(hwc->config);
- return;
- }
-
- if (event->attr.exclude_host)
- cpuc->intel_ctrl_guest_mask |= (1ull << hwc->idx);
- if (event->attr.exclude_guest)
- cpuc->intel_ctrl_host_mask |= (1ull << hwc->idx);
-
- if (unlikely(event_is_checkpointed(event)))
- cpuc->intel_cp_status |= (1ull << hwc->idx);
+ int idx = hwc->idx;

if (unlikely(event->attr.precise_ip))
intel_pmu_pebs_enable(event);

- if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
+ if (idx < INTEL_PMC_IDX_FIXED) {
+ intel_set_masks(event, idx);
+ __x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
+ } else if (idx < INTEL_PMC_IDX_FIXED_BTS) {
+ intel_set_masks(event, idx);
intel_pmu_enable_fixed(event);
- return;
+ } else if (idx == INTEL_PMC_IDX_FIXED_BTS) {
+ if (!__this_cpu_read(cpu_hw_events.enabled))
+ return;
+ intel_pmu_enable_bts(hwc->config);
}
-
- __x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
}

static void intel_pmu_add_event(struct perf_event *event)
--
2.21.3