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perf intel-tpebs: Add mutex for tpebs_results

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Ensure sample reader isn't racing with events being added/removed.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Weilin Wang <weilin.wang@intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Andreas Färber <afaerber@suse.de>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Link: https://lore.kernel.org/r/20250414174134.3095492-12-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers
2025-04-14 10:41:29 -07:00
committed by Arnaldo Carvalho de Melo
parent ea61db61d9
commit 8174392049
1 changed files with 46 additions and 8 deletions
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54
tools/perf/util/intel-tpebs.c
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@@ -16,6 +16,7 @@
#include "debug.h"
#include "evlist.h"
#include "evsel.h"
#include "mutex.h"
#include "session.h"
#include "tool.h"
#include "cpumap.h"
@@ -32,6 +33,7 @@ bool tpebs_recording;
static LIST_HEAD(tpebs_results);
static pthread_t tpebs_reader_thread;
static struct child_process tpebs_cmd;
static struct mutex tpebs_mtx;
struct tpebs_retire_lat {
struct list_head nd;
@@ -51,6 +53,19 @@ struct tpebs_retire_lat {
static struct tpebs_retire_lat *tpebs_retire_lat__find(struct evsel *evsel);
static void tpebs_mtx_init(void)
{
mutex_init(&tpebs_mtx);
}
static struct mutex *tpebs_mtx_get(void)
{
static pthread_once_t tpebs_mtx_once = PTHREAD_ONCE_INIT;
pthread_once(&tpebs_mtx_once, tpebs_mtx_init);
return &tpebs_mtx;
}
static int evsel__tpebs_start_perf_record(struct evsel *evsel, int control_fd[], int ack_fd[])
{
const char **record_argv;
@@ -59,13 +74,15 @@ static int evsel__tpebs_start_perf_record(struct evsel *evsel, int control_fd[],
char cpumap_buf[50];
struct tpebs_retire_lat *t;
mutex_lock(tpebs_mtx_get());
list_for_each_entry(t, &tpebs_results, nd)
tpebs_event_size++;
record_argv = malloc((10 + 2 * tpebs_event_size) * sizeof(*record_argv));
if (!record_argv)
if (!record_argv) {
mutex_unlock(tpebs_mtx_get());
return -ENOMEM;
}
record_argv[i++] = "perf";
record_argv[i++] = "record";
record_argv[i++] = "-W";
@@ -101,6 +118,7 @@ static int evsel__tpebs_start_perf_record(struct evsel *evsel, int control_fd[],
list_for_each_entry(t, &tpebs_results, nd)
t->started = true;
mutex_unlock(tpebs_mtx_get());
return ret;
}
@@ -112,9 +130,12 @@ static int process_sample_event(const struct perf_tool *tool __maybe_unused,
{
struct tpebs_retire_lat *t;
mutex_lock(tpebs_mtx_get());
t = tpebs_retire_lat__find(evsel);
if (!t)
if (!t) {
mutex_unlock(tpebs_mtx_get());
return -EINVAL;
}
/*
* Need to handle per core results? We are assuming average retire
* latency value will be used. Save the number of samples and the sum of
@@ -123,6 +144,7 @@ static int process_sample_event(const struct perf_tool *tool __maybe_unused,
t->count += 1;
t->sum += sample->retire_lat;
t->val = (double) t->sum / t->count;
mutex_unlock(tpebs_mtx_get());
return 0;
}
@@ -229,7 +251,6 @@ static struct tpebs_retire_lat *tpebs_retire_lat__new(struct evsel *evsel)
return NULL;
}
result->evsel = evsel;
list_add_tail(&result->nd, &tpebs_results);
return result;
}
@@ -282,15 +303,22 @@ static struct tpebs_retire_lat *tpebs_retire_lat__find(struct evsel *evsel)
static int evsel__tpebs_prepare(struct evsel *evsel)
{
struct evsel *pos;
struct tpebs_retire_lat *tpebs_event = tpebs_retire_lat__find(evsel);
struct tpebs_retire_lat *tpebs_event;
mutex_lock(tpebs_mtx_get());
tpebs_event = tpebs_retire_lat__find(evsel);
if (tpebs_event) {
/* evsel, or an identically named one, was already prepared. */
mutex_unlock(tpebs_mtx_get());
return 0;
}
tpebs_event = tpebs_retire_lat__new(evsel);
if (!tpebs_event)
if (!tpebs_event) {
mutex_unlock(tpebs_mtx_get());
return -ENOMEM;
}
list_add_tail(&tpebs_event->nd, &tpebs_results);
mutex_unlock(tpebs_mtx_get());
/*
* Eagerly prepare all other evsels on the list to try to ensure that by
@@ -317,6 +345,7 @@ static int evsel__tpebs_prepare(struct evsel *evsel)
int evsel__tpebs_open(struct evsel *evsel)
{
int ret;
bool tpebs_empty;
/* We should only run tpebs_start when tpebs_recording is enabled. */
if (!tpebs_recording)
@@ -336,7 +365,10 @@ int evsel__tpebs_open(struct evsel *evsel)
if (ret)
return ret;
if (!list_empty(&tpebs_results)) {
mutex_lock(tpebs_mtx_get());
tpebs_empty = list_empty(&tpebs_results);
mutex_unlock(tpebs_mtx_get());
if (!tpebs_empty) {
struct pollfd pollfd = { .events = POLLIN, };
int control_fd[2], ack_fd[2], len;
char ack_buf[8];
@@ -436,8 +468,10 @@ int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
*/
tpebs_stop();
mutex_lock(tpebs_mtx_get());
t = tpebs_retire_lat__find(evsel);
val = rint(t->val);
mutex_unlock(tpebs_mtx_get());
if (old_count) {
count->val = old_count->val + val;
@@ -460,9 +494,13 @@ int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
*/
void evsel__tpebs_close(struct evsel *evsel)
{
struct tpebs_retire_lat *t = tpebs_retire_lat__find(evsel);
struct tpebs_retire_lat *t;
mutex_lock(tpebs_mtx_get());
t = tpebs_retire_lat__find(evsel);
list_del_init(&t->nd);
tpebs_retire_lat__delete(t);
mutex_unlock(tpebs_mtx_get());
if (list_empty(&tpebs_results))
tpebs_stop();