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perf intel-tpebs: Simplify tpebs_cmd

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No need to dynamically allocate when there is 1. tpebs_pid duplicates
tpebs_cmd.pid, so remove. Use 0 as the uninitialized value (PID == 0
is reserved for the kernel) rather than -1.

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/20250414174134.3095492-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2025-04-14 10:41:20 -07:00 committed by Arnaldo Carvalho de Melo
parent eb493c28e9
commit 9e0ef3ec62
1 changed files with 18 additions and 37 deletions
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55
tools/perf/util/intel-tpebs.c
View File

@ -28,11 +28,10 @@
#define PERF_DATA "-"
bool tpebs_recording;
static pid_t tpebs_pid = -1;
static size_t tpebs_event_size;
static LIST_HEAD(tpebs_results);
static pthread_t tpebs_reader_thread;
static struct child_process *tpebs_cmd;
static struct child_process tpebs_cmd;
struct tpebs_retire_lat {
struct list_head nd;
@ -83,16 +82,6 @@ static int get_perf_record_args(const char **record_argv, char buf[],
return 0;
}
static int prepare_run_command(const char **argv)
{
tpebs_cmd = zalloc(sizeof(struct child_process));
if (!tpebs_cmd)
return -ENOMEM;
tpebs_cmd->argv = argv;
tpebs_cmd->out = -1;
return 0;
}
static int start_perf_record(int control_fd[], int ack_fd[],
const char *cpumap_buf)
{
@ -110,10 +99,10 @@ static int start_perf_record(int control_fd[], int ack_fd[],
if (ret)
goto out;
ret = prepare_run_command(record_argv);
if (ret)
goto out;
ret = start_command(tpebs_cmd);
assert(tpebs_cmd.pid == 0);
tpebs_cmd.argv = record_argv;
tpebs_cmd.out = -1;
ret = start_command(&tpebs_cmd);
out:
free(record_argv);
return ret;
@ -156,14 +145,13 @@ static int process_feature_event(struct perf_session *session,
return 0;
}
static void *__sample_reader(void *arg)
static void *__sample_reader(void *arg __maybe_unused)
{
struct child_process *child = arg;
struct perf_session *session;
struct perf_data data = {
.mode = PERF_DATA_MODE_READ,
.path = PERF_DATA,
.file.fd = child->out,
.file.fd = tpebs_cmd.out,
};
struct perf_tool tool;
@ -189,12 +177,12 @@ static int tpebs_stop(void)
int ret = 0;
/* Like tpebs_start, we should only run tpebs_end once. */
if (tpebs_pid != -1) {
kill(tpebs_cmd->pid, SIGTERM);
tpebs_pid = -1;
if (tpebs_cmd.pid != 0) {
kill(tpebs_cmd.pid, SIGTERM);
pthread_join(tpebs_reader_thread, NULL);
close(tpebs_cmd->out);
ret = finish_command(tpebs_cmd);
close(tpebs_cmd.out);
ret = finish_command(&tpebs_cmd);
tpebs_cmd.pid = 0;
if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
ret = 0;
}
@ -219,7 +207,7 @@ int tpebs_start(struct evlist *evsel_list)
* We should only run tpebs_start when tpebs_recording is enabled.
* And we should only run it once with all the required events.
*/
if (tpebs_pid != -1 || !tpebs_recording)
if (tpebs_cmd.pid != 0 || !tpebs_recording)
return 0;
cpu_map__snprint(evsel_list->core.user_requested_cpus, cpumap_buf, sizeof(cpumap_buf));
@ -284,10 +272,11 @@ int tpebs_start(struct evlist *evsel_list)
ret = start_perf_record(control_fd, ack_fd, cpumap_buf);
if (ret)
goto out;
tpebs_pid = tpebs_cmd->pid;
if (pthread_create(&tpebs_reader_thread, NULL, __sample_reader, tpebs_cmd)) {
kill(tpebs_cmd->pid, SIGTERM);
close(tpebs_cmd->out);
if (pthread_create(&tpebs_reader_thread, /*attr=*/NULL, __sample_reader,
/*arg=*/NULL)) {
kill(tpebs_cmd.pid, SIGTERM);
close(tpebs_cmd.out);
pr_err("Could not create thread to process sample data.\n");
ret = -1;
goto out;
@ -416,18 +405,10 @@ void tpebs_delete(void)
{
struct tpebs_retire_lat *r, *rtmp;
if (tpebs_pid == -1)
return;
tpebs_stop();
list_for_each_entry_safe(r, rtmp, &tpebs_results, nd) {
list_del_init(&r->nd);
tpebs_retire_lat__delete(r);
}
if (tpebs_cmd) {
free(tpebs_cmd);
tpebs_cmd = NULL;
}
}