[RFC PATCH v3 4/6] perf stat: Create another thread for sample data processing

From: weilin . wang
Date: Fri Mar 01 2024 - 19:12:28 EST


From: Weilin Wang <weilin.wang@xxxxxxxxx>

Another thread is required to synchronize between perf stat and perf record
when we pass data through pipe.

Signed-off-by: Weilin Wang <weilin.wang@xxxxxxxxx>
---
tools/perf/builtin-stat.c | 58 +++++++++++++++++++++++----------------
1 file changed, 34 insertions(+), 24 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 3e5865572266..2372175d3408 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -777,7 +777,6 @@ static int process_sample_event(struct perf_tool *tool,
const char *evname;
struct tpebs_retire_lat *t;

- pr_debug("entering function %s\n ", __func__);
evname = evsel__name(evsel);

pr_debug("[%03d] ", sample->cpu);
@@ -808,9 +807,9 @@ static int process_feature_event(struct perf_session *session,
return 0;
}

-static int __cmd_script(struct child_process *cmd __maybe_unused)
+static void *__cmd_script(void *arg __maybe_unused)
{
- int err = 0;
+ struct child_process *cmd = arg;
struct perf_session *session;
struct perf_data data = {
.mode = PERF_DATA_MODE_READ,
@@ -826,29 +825,15 @@ static int __cmd_script(struct child_process *cmd __maybe_unused)
.attr = perf_event__process_attr,
},
};
- struct tpebs_event *e;
-
- list_for_each_entry(e, &stat_config.tpebs_events, nd) {
- struct tpebs_retire_lat *new = malloc(sizeof(struct tpebs_retire_lat));
-
- if (!new)
- return -1;
- new->name = strdup(e->name);
- new->tpebs_name = strdup(e->tpebs_name);
- new->count = 0;
- new->sum = 0;
- list_add_tail(&new->nd, &stat_config.tpebs_results);
- }

- kill(cmd->pid, SIGTERM);
session = perf_session__new(&data, &script.tool);
if (IS_ERR(session))
- return PTR_ERR(session);
+ return NULL;
script.session = session;
- err = perf_session__process_events(session);
+ perf_session__process_events(session);
perf_session__delete(session);

- return err;
+ return NULL;
}

static int __run_perf_stat(int argc, const char **argv, int run_idx)
@@ -868,15 +853,37 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
int err;
bool second_pass = false;
struct child_process cmd;
+ pthread_t thread_script;

//Prepare perf record for sampling event retire_latency before fork and prepare workload
if (stat_config.tpebs_event_size > 0) {
int ret;

+ struct tpebs_event *e;
pr_debug("perf stat pid = %d\n", getpid());
ret = prepare_perf_record(&cmd);
if (ret)
return ret;
+
+ list_for_each_entry(e, &stat_config.tpebs_events, nd) {
+ struct tpebs_retire_lat *new = malloc(sizeof(struct tpebs_retire_lat));
+
+ if (!new)
+ return -1;
+ new->name = strdup(e->name);
+ new->tpebs_name = strdup(e->tpebs_name);
+ new->count = 0;
+ new->sum = 0;
+ list_add_tail(&new->nd, &stat_config.tpebs_results);
+ }
+
+ if (pthread_create(&thread_script, NULL, __cmd_script, &cmd)) {
+ kill(cmd.pid, SIGTERM);
+ close(cmd.out);
+ pr_err("Could not create thread to process sample data.\n");
+ return -1;
+ }
+ sleep(2);
}

if (forks) {
@@ -1087,12 +1094,15 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
if (stat_config.tpebs_event_size > 0) {
int ret;

- pr_debug("pid = %d\n", getpid());
- pr_debug("cmd.pid = %d\n", cmd.pid);
+ pr_debug("Workload finished, finishing record\n");
+ pr_debug("Perf stat pid = %d, Perf record pid = %d\n", getpid(), cmd.pid);

- ret = __cmd_script(&cmd);
+ kill(cmd.pid, SIGTERM);
+ pthread_join(thread_script, NULL);
close(cmd.out);
- pr_debug("%d\n", ret);
+ ret = finish_command(&cmd);
+ if (ret != -ERR_RUN_COMMAND_WAITPID_SIGNAL)
+ return ret;
}

if (stat_config.walltime_run_table)
--
2.43.0