[PATCH v12 06/16] perf record: Stop threads in the end of trace streaming

Alexey Bayduraev
2021-11-23T14:09:18Z

Signal thread to terminate by closing write fd of msg pipe.
Receive THREAD_MSG__READY message as the confirmation of the
thread's termination. Stop threads created for parallel trace
streaming prior their stats processing.

Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Reviewed-by: Riccardo Mancini <rickyman7@gmail.com>
Tested-by: Riccardo Mancini <rickyman7@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
tools/perf/builtin-record.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index fcd915e2e5ca..7a9c0c7daeaa 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -112,6 +112,16 @@ struct record_thread {

static __thread struct record_thread *thread;

+enum thread_msg {
+ THREAD_MSG__UNDEFINED = 0,
+ THREAD_MSG__READY,
+ THREAD_MSG__MAX,
+};
+
+static const char *thread_msg_tags[THREAD_MSG__MAX] = {
+ "UNDEFINED", "READY"
+};
+
struct record {
struct perf_tool tool;
struct record_opts opts;
@@ -1890,6 +1900,23 @@ static void record__uniquify_name(struct record *rec)
}
}

+static int record__terminate_thread(struct record_thread *thread_data)
+{
+ int res;
+ enum thread_msg ack = THREAD_MSG__UNDEFINED;
+ pid_t tid = thread_data->tid;
+
+ close(thread_data->pipes.msg[1]);
+ thread_data->pipes.msg[1] = -1;
+ res = read(thread_data->pipes.ack[0], &ack, sizeof(ack));
+ if (res != -1)
+ pr_debug2("threads[%d]: sent %s\n", tid, thread_msg_tags[ack]);
+ else
+ pr_err("threads[%d]: failed to receive message from tid: %d\n", thread->tid, tid);
+
+ return 0;
+}
+
static int record__start_threads(struct record *rec)
{
struct record_thread *thread_data = rec->thread_data;
@@ -1906,6 +1933,9 @@ static int record__stop_threads(struct record *rec)
int t;
struct record_thread *thread_data = rec->thread_data;

+ for (t = 1; t < rec->nr_threads; t++)
+ record__terminate_thread(&thread_data[t]);
+
for (t = 0; t < rec->nr_threads; t++)
rec->samples += thread_data[t].samples;

--
2.19.0