[PATCH v8 04/22] perf record: Stop threads in the end of trace streaming

From: Alexey Bayduraev
Date: Wed Jun 30 2021 - 11:55:40 EST


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@xxxxxxxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxx>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@xxxxxxxxxxxxxxx>
---
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 3935c0fabe01..82a21da2af16 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -112,6 +112,16 @@ struct thread_data {

static __thread struct thread_data *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;
@@ -1857,6 +1867,23 @@ static void record__uniquify_name(struct record *rec)
}
}

+static int record__terminate_thread(struct thread_data *thread_data)
+{
+ int res;
+ enum thread_msg ack = THREAD_MSG__UNDEFINED;
+ pid_t tid = thread_data->tid;
+
+ close(thread_data->pipes.msg[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 recv msg=%s from tid=%d\n",
+ thread->tid, thread_msg_tags[ack], tid);
+
+ return 0;
+}
+
static int record__start_threads(struct record *rec)
{
struct thread_data *thread_data = rec->thread_data;
@@ -1873,6 +1900,9 @@ static int record__stop_threads(struct record *rec, unsigned long *waking)
int t;
struct thread_data *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;
*waking += thread_data[t].waking;
--
2.19.0