* [PATCH v3 1/4] perf: Support PERF_SAMPLE_READ with inherit_stat
2024-03-22 13:04 [PATCH v3 0/4] perf: Support PERF_SAMPLE_READ with inherit_stat Ben Gainey
@ 2024-03-22 13:04 ` Ben Gainey
2024-03-22 13:04 ` [PATCH v3 2/4] tools/perf: Track where perf_sample_ids need per-thread periods Ben Gainey
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Ben Gainey @ 2024-03-22 13:04 UTC (permalink / raw)
To: peterz, mingo, acme, namhyung
Cc: james.clark, mark.rutland, alexander.shishkin, jolsa, irogers,
adrian.hunter, linux-perf-users, linux-kernel, Ben Gainey
This change allows events to use PERF_SAMPLE READ with inherit
so long as both inherit_stat and PERF_SAMPLE_TID are set.
In this configuration, an event will be inherited into any
child processes / threads, allowing convenient profiling of a
multiprocess or multithreaded application, whilst allowing
profiling tools to collect per-thread samples, in particular
of groups of counters.
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
---
include/linux/perf_event.h | 1 +
kernel/events/core.c | 62 +++++++++++++++++++++++++++++---------
2 files changed, 48 insertions(+), 15 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index d2a15c0c6f8a..7d405dff6694 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -932,6 +932,7 @@ struct perf_event_context {
int nr_task_data;
int nr_stat;
+ int nr_stat_read;
int nr_freq;
int rotate_disable;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f0f0f71213a1..870a7dbd8d5f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1767,6 +1767,18 @@ perf_event_groups_next(struct perf_event *event, struct pmu *pmu)
event = rb_entry_safe(rb_next(&event->group_node), \
typeof(*event), group_node))
+/*
+ * Does the event attribute request inherit with PERF_SAMPLE_READ
+ */
+#define perf_attr_has_inherit_and_sample_read(attr) \
+ ((attr)->inherit && ((attr)->sample_type & PERF_SAMPLE_READ))
+
+/*
+ * Does the event request an attribte that requests inherit with PERF_SAMPLE_READ
+ */
+#define perf_event_has_inherit_and_sample_read(event) \
+ perf_attr_has_inherit_and_sample_read(&((event)->attr))
+
/*
* Add an event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
@@ -1795,8 +1807,11 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
ctx->nr_events++;
if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
ctx->nr_user++;
- if (event->attr.inherit_stat)
+ if (event->attr.inherit_stat) {
ctx->nr_stat++;
+ if (perf_event_has_inherit_and_sample_read(event))
+ ctx->nr_stat_read++;
+ }
if (event->state > PERF_EVENT_STATE_OFF)
perf_cgroup_event_enable(event, ctx);
@@ -2019,8 +2034,11 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
ctx->nr_events--;
if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
ctx->nr_user--;
- if (event->attr.inherit_stat)
+ if (event->attr.inherit_stat) {
ctx->nr_stat--;
+ if (perf_event_has_inherit_and_sample_read(event))
+ ctx->nr_stat_read--;
+ }
list_del_rcu(&event->event_entry);
@@ -3529,11 +3547,19 @@ perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
perf_ctx_disable(ctx, false);
/* PMIs are disabled; ctx->nr_pending is stable. */
- if (local_read(&ctx->nr_pending) ||
+ if (ctx->nr_stat_read ||
+ next_ctx->nr_stat_read ||
+ local_read(&ctx->nr_pending) ||
local_read(&next_ctx->nr_pending)) {
/*
* Must not swap out ctx when there's pending
* events that rely on the ctx->task relation.
+ *
+ * Likewise, when a context contains inherit +
+ * inherit_stat + SAMPLE_READ events they
+ * should be switched out using the slow path
+ * so that they are treated as if they were
+ * distinct contexts.
*/
raw_spin_unlock(&next_ctx->lock);
rcu_read_unlock();
@@ -4533,8 +4559,11 @@ static void __perf_event_read(void *info)
raw_spin_unlock(&ctx->lock);
}
-static inline u64 perf_event_count(struct perf_event *event)
+static inline u64 perf_event_count(struct perf_event *event, bool self_value_only)
{
+ if (self_value_only && perf_event_has_inherit_and_sample_read(event))
+ return local64_read(&event->count);
+
return local64_read(&event->count) + atomic64_read(&event->child_count);
}
@@ -5454,7 +5483,7 @@ static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *
mutex_lock(&event->child_mutex);
(void)perf_event_read(event, false);
- total += perf_event_count(event);
+ total += perf_event_count(event, false);
*enabled += event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
@@ -5463,7 +5492,7 @@ static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *
list_for_each_entry(child, &event->child_list, child_list) {
(void)perf_event_read(child, false);
- total += perf_event_count(child);
+ total += perf_event_count(child, false);
*enabled += child->total_time_enabled;
*running += child->total_time_running;
}
@@ -5545,14 +5574,14 @@ static int __perf_read_group_add(struct perf_event *leader,
/*
* Write {count,id} tuples for every sibling.
*/
- values[n++] += perf_event_count(leader);
+ values[n++] += perf_event_count(leader, false);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
if (read_format & PERF_FORMAT_LOST)
values[n++] = atomic64_read(&leader->lost_samples);
for_each_sibling_event(sub, leader) {
- values[n++] += perf_event_count(sub);
+ values[n++] += perf_event_count(sub, false);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
if (read_format & PERF_FORMAT_LOST)
@@ -6132,7 +6161,7 @@ void perf_event_update_userpage(struct perf_event *event)
++userpg->lock;
barrier();
userpg->index = perf_event_index(event);
- userpg->offset = perf_event_count(event);
+ userpg->offset = perf_event_count(event, false);
if (userpg->index)
userpg->offset -= local64_read(&event->hw.prev_count);
@@ -7200,7 +7229,7 @@ static void perf_output_read_one(struct perf_output_handle *handle,
u64 values[5];
int n = 0;
- values[n++] = perf_event_count(event);
+ values[n++] = perf_event_count(event, true);
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
values[n++] = enabled +
atomic64_read(&event->child_total_time_enabled);
@@ -7245,7 +7274,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
(leader->state == PERF_EVENT_STATE_ACTIVE))
leader->pmu->read(leader);
- values[n++] = perf_event_count(leader);
+ values[n++] = perf_event_count(leader, true);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
if (read_format & PERF_FORMAT_LOST)
@@ -7260,7 +7289,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
(sub->state == PERF_EVENT_STATE_ACTIVE))
sub->pmu->read(sub);
- values[n++] = perf_event_count(sub);
+ values[n++] = perf_event_count(sub, false);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
if (read_format & PERF_FORMAT_LOST)
@@ -12010,10 +12039,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
local64_set(&hwc->period_left, hwc->sample_period);
/*
- * We currently do not support PERF_SAMPLE_READ on inherited events.
+ * We do not support PERF_SAMPLE_READ on inherited events unless
+ * inherit_stat and PERF_SAMPLE_TID are also selected, which allows
+ * inherited events to collect per-thread samples.
* See perf_output_read().
*/
- if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
+ if (perf_attr_has_inherit_and_sample_read(attr)
+ && !(attr->inherit_stat && (attr->sample_type & PERF_SAMPLE_TID)))
goto err_ns;
if (!has_branch_stack(event))
@@ -13037,7 +13069,7 @@ static void sync_child_event(struct perf_event *child_event)
perf_event_read_event(child_event, task);
}
- child_val = perf_event_count(child_event);
+ child_val = perf_event_count(child_event, false);
/*
* Add back the child's count to the parent's count:
--
2.44.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v3 2/4] tools/perf: Track where perf_sample_ids need per-thread periods
2024-03-22 13:04 [PATCH v3 0/4] perf: Support PERF_SAMPLE_READ with inherit_stat Ben Gainey
2024-03-22 13:04 ` [PATCH v3 1/4] " Ben Gainey
@ 2024-03-22 13:04 ` Ben Gainey
2024-03-22 13:04 ` [PATCH v3 3/4] tools/perf: Correctly calculate sample period for inherited SAMPLE_READ values Ben Gainey
2024-03-22 13:04 ` [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events Ben Gainey
3 siblings, 0 replies; 7+ messages in thread
From: Ben Gainey @ 2024-03-22 13:04 UTC (permalink / raw)
To: peterz, mingo, acme, namhyung
Cc: james.clark, mark.rutland, alexander.shishkin, jolsa, irogers,
adrian.hunter, linux-perf-users, linux-kernel, Ben Gainey
perf_sample_ids and related evlist/evsel code are modified to track
which events combine inherit+inherit_stat+PERF_SAMPLE_READ.
Events with this combination of properties must be handled differently
when tracking each streams sample period, as their stream-id is now only
unique per thread, rather than globally unique.
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
---
tools/lib/perf/evlist.c | 1 +
tools/lib/perf/evsel.c | 7 +++++++
tools/lib/perf/include/internal/evsel.h | 9 +++++++++
3 files changed, 17 insertions(+)
diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index 058e3ff10f9b..c585c49491a5 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -255,6 +255,7 @@ static void perf_evlist__id_hash(struct perf_evlist *evlist,
sid->id = id;
sid->evsel = evsel;
+ sid->period_per_thread = perf_evsel__attr_has_per_thread_sample_period(evsel);
hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
hlist_add_head(&sid->node, &evlist->heads[hash]);
}
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index c07160953224..dd60ee0557d8 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -537,6 +537,13 @@ void perf_evsel__free_id(struct perf_evsel *evsel)
evsel->ids = 0;
}
+bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel)
+{
+ return (evsel->attr.sample_type & PERF_SAMPLE_READ)
+ && evsel->attr.inherit
+ && evsel->attr.inherit_stat;
+}
+
void perf_counts_values__scale(struct perf_counts_values *count,
bool scale, __s8 *pscaled)
{
diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h
index 5cd220a61962..8dd58149986c 100644
--- a/tools/lib/perf/include/internal/evsel.h
+++ b/tools/lib/perf/include/internal/evsel.h
@@ -36,6 +36,13 @@ struct perf_sample_id {
/* Holds total ID period value for PERF_SAMPLE_READ processing. */
u64 period;
+
+ /*
+ * When inherit+inherit_stat is combined with PERF_SAMPLE_READ, the
+ * period value is per (sample_id, thread) tuple, rather than per
+ * sample_id.
+ */
+ bool period_per_thread;
};
struct perf_evsel {
@@ -88,4 +95,6 @@ int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter);
int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads);
void perf_evsel__free_id(struct perf_evsel *evsel);
+bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel);
+
#endif /* __LIBPERF_INTERNAL_EVSEL_H */
--
2.44.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v3 3/4] tools/perf: Correctly calculate sample period for inherited SAMPLE_READ values
2024-03-22 13:04 [PATCH v3 0/4] perf: Support PERF_SAMPLE_READ with inherit_stat Ben Gainey
2024-03-22 13:04 ` [PATCH v3 1/4] " Ben Gainey
2024-03-22 13:04 ` [PATCH v3 2/4] tools/perf: Track where perf_sample_ids need per-thread periods Ben Gainey
@ 2024-03-22 13:04 ` Ben Gainey
2024-03-22 13:04 ` [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events Ben Gainey
3 siblings, 0 replies; 7+ messages in thread
From: Ben Gainey @ 2024-03-22 13:04 UTC (permalink / raw)
To: peterz, mingo, acme, namhyung
Cc: james.clark, mark.rutland, alexander.shishkin, jolsa, irogers,
adrian.hunter, linux-perf-users, linux-kernel, Ben Gainey
Sample period calculation is updated to take into account the fact that
the stream-id for events with inherit+inherit_stat+PERF_SAMPLE_READ
is now unique per thread, rather than globally unique.
perf_sample_id is modified to support tracking per-stream+per-thread
values, along with the existing global per-stream values. In the
per-thread case, values are stored in a hash by tid.
deliver_sample_value is modified to correctly locate the previous
sample storage based on the attribute, stream id and thread id.
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
---
tools/lib/perf/evsel.c | 41 ++++++++++++++++++++++
tools/lib/perf/include/internal/evsel.h | 46 +++++++++++++++++++++++--
tools/perf/util/session.c | 11 ++++--
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index dd60ee0557d8..2bdba78cc43e 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -5,6 +5,7 @@
#include <perf/evsel.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
+#include <linux/hash.h>
#include <linux/list.h>
#include <internal/evsel.h>
#include <linux/zalloc.h>
@@ -23,6 +24,7 @@ void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
int idx)
{
INIT_LIST_HEAD(&evsel->node);
+ INIT_LIST_HEAD(&evsel->period_per_thread_periods);
evsel->attr = *attr;
evsel->idx = idx;
evsel->leader = evsel;
@@ -531,10 +533,17 @@ int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
void perf_evsel__free_id(struct perf_evsel *evsel)
{
+ struct perf_sample_id_period *pos, *n;
+
xyarray__delete(evsel->sample_id);
evsel->sample_id = NULL;
zfree(&evsel->id);
evsel->ids = 0;
+
+ perf_evsel_for_each_per_thread_period_safe(evsel, n, pos) {
+ list_del_init(&pos->node);
+ zfree(pos);
+ }
}
bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel)
@@ -544,6 +553,38 @@ bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel)
&& evsel->attr.inherit_stat;
}
+u64 *perf_sample_id__get_period_storage(struct perf_sample_id *sid, u32 tid)
+{
+ struct hlist_head *head;
+ struct perf_sample_id_period *res;
+ int hash;
+
+ if (!sid->period_per_thread)
+ return &sid->period;
+
+ hash = hash_32(tid, PERF_SAMPLE_ID__HLIST_BITS);
+ head = &sid->periods[hash];
+
+ hlist_for_each_entry(res, head, hnode)
+ if (res->tid == tid)
+ return &res->period;
+
+ if (sid->evsel == NULL)
+ return NULL;
+
+ res = zalloc(sizeof(struct perf_sample_id_period));
+ if (res == NULL)
+ return NULL;
+
+ INIT_LIST_HEAD(&res->node);
+ res->tid = tid;
+
+ list_add_tail(&res->node, &sid->evsel->period_per_thread_periods);
+ hlist_add_head(&res->hnode, &sid->periods[hash]);
+
+ return &res->period;
+}
+
void perf_counts_values__scale(struct perf_counts_values *count,
bool scale, __s8 *pscaled)
{
diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h
index 8dd58149986c..52ec2edf628b 100644
--- a/tools/lib/perf/include/internal/evsel.h
+++ b/tools/lib/perf/include/internal/evsel.h
@@ -11,6 +11,32 @@
struct perf_thread_map;
struct xyarray;
+/**
+ * The per-thread accumulated period storage node.
+ */
+struct perf_sample_id_period {
+ struct list_head node;
+ struct hlist_node hnode;
+ /* The thread that the values belongs to */
+ u32 tid;
+ /* Holds total ID period value for PERF_SAMPLE_READ processing. */
+ u64 period;
+};
+
+/**
+ * perf_evsel_for_each_per_thread_period_safe - safely iterate thru all the
+ * period_per_thread_periods
+ * @evlist:perf_evsel instance to iterate
+ * @item: struct perf_sample_id_period iterator
+ * @tmp: struct perf_sample_id_period temp iterator
+ */
+#define perf_evsel_for_each_per_thread_period_safe(evsel, tmp, item) \
+ list_for_each_entry_safe(item, tmp, &(evsel)->period_per_thread_periods, node)
+
+
+#define PERF_SAMPLE_ID__HLIST_BITS 4
+#define PERF_SAMPLE_ID__HLIST_SIZE (1 << PERF_SAMPLE_ID__HLIST_BITS)
+
/*
* Per fd, to map back from PERF_SAMPLE_ID to evsel, only used when there are
* more than one entry in the evlist.
@@ -19,6 +45,7 @@ struct perf_sample_id {
struct hlist_node node;
u64 id;
struct perf_evsel *evsel;
+
/*
* 'idx' will be used for AUX area sampling. A sample will have AUX area
* data that will be queued for decoding, where there are separate
@@ -34,8 +61,18 @@ struct perf_sample_id {
pid_t machine_pid;
struct perf_cpu vcpu;
- /* Holds total ID period value for PERF_SAMPLE_READ processing. */
- u64 period;
+ union {
+ /*
+ * Holds total ID period value for PERF_SAMPLE_READ processing
+ * (when period is not per-thread).
+ */
+ u64 period;
+ /*
+ * Holds total ID period value for PERF_SAMPLE_READ processing
+ * (when period is per-thread).
+ */
+ struct hlist_head periods[PERF_SAMPLE_ID__HLIST_SIZE];
+ };
/*
* When inherit+inherit_stat is combined with PERF_SAMPLE_READ, the
@@ -65,6 +102,9 @@ struct perf_evsel {
u32 ids;
struct perf_evsel *leader;
+ /* Where period_per_thread is true, stores the per-thread values */
+ struct list_head period_per_thread_periods;
+
/* parse modifier helper */
int nr_members;
/*
@@ -97,4 +137,6 @@ void perf_evsel__free_id(struct perf_evsel *evsel);
bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel);
+u64 *perf_sample_id__get_period_storage(struct perf_sample_id *sid, u32 tid);
+
#endif /* __LIBPERF_INTERNAL_EVSEL_H */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 199d3e8df315..2d6a92374847 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1478,14 +1478,19 @@ static int deliver_sample_value(struct evlist *evlist,
{
struct perf_sample_id *sid = evlist__id2sid(evlist, v->id);
struct evsel *evsel;
+ u64 *storage = NULL;
if (sid) {
+ storage = perf_sample_id__get_period_storage(sid, sample->tid);
+ }
+
+ if (storage) {
sample->id = v->id;
- sample->period = v->value - sid->period;
- sid->period = v->value;
+ sample->period = v->value - *storage;
+ *storage = v->value;
}
- if (!sid || sid->evsel == NULL) {
+ if (!storage || sid->evsel == NULL) {
++evlist->stats.nr_unknown_id;
return 0;
}
--
2.44.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events
2024-03-22 13:04 [PATCH v3 0/4] perf: Support PERF_SAMPLE_READ with inherit_stat Ben Gainey
` (2 preceding siblings ...)
2024-03-22 13:04 ` [PATCH v3 3/4] tools/perf: Correctly calculate sample period for inherited SAMPLE_READ values Ben Gainey
@ 2024-03-22 13:04 ` Ben Gainey
2024-03-22 14:18 ` Ben Gainey
3 siblings, 1 reply; 7+ messages in thread
From: Ben Gainey @ 2024-03-22 13:04 UTC (permalink / raw)
To: peterz, mingo, acme, namhyung
Cc: james.clark, mark.rutland, alexander.shishkin, jolsa, irogers,
adrian.hunter, linux-perf-users, linux-kernel, Ben Gainey
This change updates evsel to allow the combination of inherit
and PERF_SAMPLE_READ.
A fallback is implemented for kernel versions where this feature is not
supported.
The user must pass --stat option to perf record to opt into this new
behaviour.
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
---
tools/perf/tests/attr/base-record | 2 +-
tools/perf/tests/attr/base-stat | 2 +-
tools/perf/tests/attr/system-wide-dummy | 2 +-
tools/perf/tests/attr/test-record-dummy-C0 | 2 +-
.../test-record-group-sampling-inherit-stat | 62 ++++++++++++++
tools/perf/util/evsel.c | 82 ++++++++++++++++++-
tools/perf/util/evsel.h | 1 +
7 files changed, 147 insertions(+), 6 deletions(-)
create mode 100644 tools/perf/tests/attr/test-record-group-sampling-inherit-stat
diff --git a/tools/perf/tests/attr/base-record b/tools/perf/tests/attr/base-record
index b44e4e6e4443..dd76fbdb628f 100644
--- a/tools/perf/tests/attr/base-record
+++ b/tools/perf/tests/attr/base-record
@@ -5,7 +5,7 @@ group_fd=-1
flags=0|8
cpu=*
type=0|1
-size=136
+size=144
config=0|1
sample_period=*
sample_type=263
diff --git a/tools/perf/tests/attr/base-stat b/tools/perf/tests/attr/base-stat
index fccd8ec4d1b0..d769e69bb4f5 100644
--- a/tools/perf/tests/attr/base-stat
+++ b/tools/perf/tests/attr/base-stat
@@ -5,7 +5,7 @@ group_fd=-1
flags=0|8
cpu=*
type=0
-size=136
+size=144
config=0
sample_period=0
sample_type=65536
diff --git a/tools/perf/tests/attr/system-wide-dummy b/tools/perf/tests/attr/system-wide-dummy
index a1e1d6a263bf..9806de3d9c9e 100644
--- a/tools/perf/tests/attr/system-wide-dummy
+++ b/tools/perf/tests/attr/system-wide-dummy
@@ -7,7 +7,7 @@ cpu=*
pid=-1
flags=8
type=1
-size=136
+size=144
config=9
sample_period=1
# PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME |
diff --git a/tools/perf/tests/attr/test-record-dummy-C0 b/tools/perf/tests/attr/test-record-dummy-C0
index 576ec48b3aaf..87f5c8db5ba1 100644
--- a/tools/perf/tests/attr/test-record-dummy-C0
+++ b/tools/perf/tests/attr/test-record-dummy-C0
@@ -10,7 +10,7 @@ cpu=0
pid=-1
flags=8
type=1
-size=136
+size=144
config=9
sample_period=4000
# PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME |
diff --git a/tools/perf/tests/attr/test-record-group-sampling-inherit-stat b/tools/perf/tests/attr/test-record-group-sampling-inherit-stat
new file mode 100644
index 000000000000..281a17acb6ae
--- /dev/null
+++ b/tools/perf/tests/attr/test-record-group-sampling-inherit-stat
@@ -0,0 +1,62 @@
+[config]
+command = record
+args = --stat --no-bpf-event -c 10000 -e '{cycles,cache-misses}:S' kill >/dev/null 2>&1
+ret = 1
+
+[event-1:base-record]
+fd=1
+group_fd=-1
+
+# cycles
+type=0
+config=0
+
+# default | PERF_SAMPLE_READ
+sample_type=87
+
+# PERF_FORMAT_ID | PERF_FORMAT_GROUP | PERF_FORMAT_LOST | PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING
+read_format=31
+task=1
+mmap=1
+comm=1
+enable_on_exec=1
+disabled=1
+
+# inherit is enabled for group sampling, as is inherit_stat
+inherit=1
+inherit_stat=1
+
+# sampling disabled
+sample_freq=0
+sample_period=10000
+freq=0
+write_backward=0
+
+[event-2:base-record]
+fd=2
+group_fd=1
+
+# cache-misses
+type=0
+config=3
+
+# default | PERF_SAMPLE_READ
+sample_type=87
+
+# PERF_FORMAT_ID | PERF_FORMAT_GROUP | PERF_FORMAT_LOST | PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING
+read_format=31
+task=0
+mmap=0
+comm=0
+enable_on_exec=0
+disabled=0
+
+# inherit is enabled for group sampling, as is inherit_stat
+inherit=1
+inherit_stat=1
+
+# sampling disabled
+sample_freq=0
+sample_period=0
+freq=0
+write_backward=0
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6d7c9c58a9bc..aec6b4f5264e 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1097,6 +1097,64 @@ static bool evsel__is_offcpu_event(struct evsel *evsel)
return evsel__is_bpf_output(evsel) && evsel__name_is(evsel, OFFCPU_EVENT);
}
+static bool evsel__has_term_type(struct evsel *evsel, enum evsel_term_type type)
+{
+ return __evsel__get_config_term(evsel, type) != NULL;
+}
+
+/*
+ * Determine whether or not an evsel can support inherit+inherit_stat+PERF_SAMPLE_READ.
+ *
+ * In order not to break existing command line behaviour, this configuration
+ * will only be enabled if certain specific requirements are met:
+ *
+ * 1) When making a system-wide capture, there is no need to support this
+ * configuration. Likewise, if the user disables inherit, or does not request
+ * inherit_stat, then the configuration is not supported.
+ * 2) If the user explicitly specifies 'freq' as a config term, then do not
+ * support this feature, as frequency counters are not compatible.
+ * 3) If the user explicitly specifies 'period' as a config term, then the
+ * feature is compatible with that event.
+ * 4) If neither was explicitly set, and the event is part of a group, then
+ * base the decision on the leader.
+ * 5) Otherwise base the decision on whether or not the user specified a period
+ * or frequency on the command line (which includes the default frequency
+ * setting).
+ */
+static bool evsel__compat_with_inherit_sample_read(struct record_opts *opts,
+ struct evsel *leader,
+ struct evsel *evsel)
+{
+ struct perf_event_attr *attr = &evsel->core.attr;
+
+ if (opts->target.system_wide)
+ return false;
+
+ if (opts->no_inherit_set || !opts->inherit_stat)
+ return false;
+
+ if (evsel__has_term_type(evsel, EVSEL__CONFIG_TERM_FREQ))
+ return false;
+
+ if (evsel__has_term_type(evsel, EVSEL__CONFIG_TERM_PERIOD))
+ return true;
+
+ if (leader && (leader != evsel)) {
+ struct perf_event_attr *ldr_att = &leader->core.attr;
+
+ if (evsel__has_term_type(leader, EVSEL__CONFIG_TERM_FREQ))
+ return false;
+
+ if (evsel__has_term_type(leader, EVSEL__CONFIG_TERM_PERIOD))
+ return true;
+
+ if (ldr_att->freq)
+ return false;
+ }
+
+ return (!attr->freq && !opts->freq);
+}
+
/*
* The enable_on_exec/disabled value strategy:
*
@@ -1133,6 +1191,9 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
int track = evsel->tracking;
bool per_cpu = opts->target.default_per_cpu && !opts->target.per_thread;
+ bool allow_inherit_stat_sample_read = evsel__compat_with_inherit_sample_read(
+ opts, leader, evsel);
+
attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
attr->inherit = !opts->no_inherit;
attr->write_backward = opts->overwrite ? 1 : 0;
@@ -1156,7 +1217,17 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
*/
if (leader->core.nr_members > 1) {
attr->read_format |= PERF_FORMAT_GROUP;
- attr->inherit = 0;
+ if (!allow_inherit_stat_sample_read)
+ attr->inherit = 0;
+ }
+
+ /*
+ * Inherit + READ requires inherit_stat, but only if freq is
+ * not set as the two are incompatible
+ */
+ if (attr->inherit && allow_inherit_stat_sample_read) {
+ attr->inherit_stat = 1;
+ evsel__set_sample_bit(evsel, TID);
}
}
@@ -1832,6 +1903,8 @@ static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus,
static void evsel__disable_missing_features(struct evsel *evsel)
{
+ if (perf_missing_features.inherit_sample_read)
+ evsel->core.attr.inherit = 0;
if (perf_missing_features.branch_counters)
evsel->core.attr.branch_sample_type &= ~PERF_SAMPLE_BRANCH_COUNTERS;
if (perf_missing_features.read_lost)
@@ -1887,7 +1960,12 @@ bool evsel__detect_missing_features(struct evsel *evsel)
* Must probe features in the order they were added to the
* perf_event_attr interface.
*/
- if (!perf_missing_features.branch_counters &&
+ if (!perf_missing_features.inherit_sample_read &&
+ evsel->core.attr.inherit && (evsel->core.attr.sample_type & PERF_SAMPLE_READ)) {
+ perf_missing_features.inherit_sample_read = true;
+ pr_debug2("Using PERF_SAMPLE_READ / :S modifier is not compatible with inherit, falling back to no-inherit.\n");
+ return true;
+ } else if (!perf_missing_features.branch_counters &&
(evsel->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS)) {
perf_missing_features.branch_counters = true;
pr_debug2("switching off branch counters support\n");
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index efbb6e848287..11cc9b8bee27 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -192,6 +192,7 @@ struct perf_missing_features {
bool weight_struct;
bool read_lost;
bool branch_counters;
+ bool inherit_sample_read;
};
extern struct perf_missing_features perf_missing_features;
--
2.44.0
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events
2024-03-22 13:04 ` [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events Ben Gainey
@ 2024-03-22 14:18 ` Ben Gainey
2024-03-22 14:31 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 7+ messages in thread
From: Ben Gainey @ 2024-03-22 14:18 UTC (permalink / raw)
To: namhyung@kernel.org, peterz@infradead.org, mingo@redhat.com,
acme@kernel.org
Cc: alexander.shishkin@linux.intel.com, Mark Rutland,
linux-kernel@vger.kernel.org, James Clark,
adrian.hunter@intel.com, linux-perf-users@vger.kernel.org,
jolsa@kernel.org, irogers@google.com
On Fri, 2024-03-22 at 13:04 +0000, Ben Gainey wrote:
> This change updates evsel to allow the combination of inherit
> and PERF_SAMPLE_READ.
>
> A fallback is implemented for kernel versions where this feature is
> not
> supported.
>
> The user must pass --stat option to perf record to opt into this new
> behaviour.
>
> Signed-off-by: Ben Gainey <ben.gainey@arm.com>
> ---
> tools/perf/tests/attr/base-record | 2 +-
> tools/perf/tests/attr/base-stat | 2 +-
> tools/perf/tests/attr/system-wide-dummy | 2 +-
> tools/perf/tests/attr/test-record-dummy-C0 | 2 +-
> .../test-record-group-sampling-inherit-stat | 62 ++++++++++++++
> tools/perf/util/evsel.c | 82
> ++++++++++++++++++-
> tools/perf/util/evsel.h | 1 +
> 7 files changed, 147 insertions(+), 6 deletions(-)
> create mode 100644 tools/perf/tests/attr/test-record-group-sampling-
> inherit-stat
>
> diff --git a/tools/perf/tests/attr/base-record
> b/tools/perf/tests/attr/base-record
> index b44e4e6e4443..dd76fbdb628f 100644
> --- a/tools/perf/tests/attr/base-record
> +++ b/tools/perf/tests/attr/base-record
> @@ -5,7 +5,7 @@ group_fd=-1
> flags=0|8
> cpu=*
> type=0|1
> -size=136
> +size=144
Sigh... this one belongs elsewhere. Too many spinning plates.
I'll have to redo this one with the correct size= value.
Regards
Ben
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 4/4] tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events
2024-03-22 14:18 ` Ben Gainey
@ 2024-03-22 14:31 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 7+ messages in thread
From: Arnaldo Carvalho de Melo @ 2024-03-22 14:31 UTC (permalink / raw)
To: Ben Gainey
Cc: namhyung@kernel.org, peterz@infradead.org, mingo@redhat.com,
alexander.shishkin@linux.intel.com, Mark Rutland,
linux-kernel@vger.kernel.org, James Clark,
adrian.hunter@intel.com, linux-perf-users@vger.kernel.org,
jolsa@kernel.org, irogers@google.com
On Fri, Mar 22, 2024 at 02:18:54PM +0000, Ben Gainey wrote:
> > +++ b/tools/perf/tests/attr/base-record
> > @@ -5,7 +5,7 @@ group_fd=-1
> > flags=0|8
> > cpu=*
> > type=0|1
> > -size=136
> > +size=144
>
> Sigh... this one belongs elsewhere. Too many spinning plates.
>
> I'll have to redo this one with the correct size= value.
It happens, thanks for noticing it and promply reporting, this is _very
much_ appreciated, saves me time. :-)
Just fix it and send a v4.
- Arnaldo
^ permalink raw reply [flat|nested] 7+ messages in thread