[PATCH v2 13/15] perf record: stop threads in the end of trace streaming

[Alexey Budankov]

Close write fd of comm.msg pipe to signal thread to terminate
and receive THREAD_MSG__READY confirmation on termination.
Accumulate thread stats into global stats to be correctly
calculated and displayed in perf tool output.

Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com>
---
 tools/perf/builtin-record.c | 64 ++++++++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3b7e9026f25b..a15642656066 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -85,6 +85,16 @@ struct switch_output {
        int              cur_file;
 };
 
+enum thread_msg {
+       THREAD_MSG__UNSUPPORTED = 0,
+       THREAD_MSG__READY,
+       THREAD_MSG__MAX,
+};
+
+static const char *thread_msg_tags[THREAD_MSG__MAX] = {
+       "UNSUPPORTED", "READY"
+};
+
 struct thread_data {
        pid_t              tid;
        struct {
@@ -1796,6 +1806,50 @@ static void hit_auxtrace_snapshot_trigger(struct record 
*rec)
        }
 }
 
+static int record__terminate_thread(struct thread_data *thread_data)
+{
+       int res;
+       enum thread_msg ack = THREAD_MSG__UNSUPPORTED;
+       pid_t tid = thread_data->tid;
+
+       close(thread_data->comm.msg[1]);
+       res = read(thread_data->comm.ack[0], &ack, sizeof(ack));
+       if (res != -1)
+               pr_debug("threads: %d -> %s\n", tid, thread_msg_tags[ack]);
+       else
+               pr_err("threads: failed to recv msg=%s from %d\n",
+                      thread_msg_tags[ack], tid);
+
+       return 0;
+}
+
+static int record__stop_threads(struct record *rec, unsigned long *waking)
+{
+       int i, j, nr_thread_data = rec->nr_thread_data;
+       struct thread_data *thread_data = rec->thread_data;
+
+       if (!record__threads_enabled(rec))
+               return 0;
+
+       for (i = 1; i < nr_thread_data; i++)
+               record__terminate_thread(&thread_data[i]);
+
+       for (i = 0; i < nr_thread_data; i++) {
+               pr_debug("threads: %d : samples %lld, wakes %ld\n",
+                        thread_data[i].tid, thread_data[i].samples,
+                        thread_data[i].waking);
+
+               rec->samples += thread_data[i].samples;
+               *waking      += thread_data[i].waking;
+               for (j = 0; j < thread_data[i].nr_mmaps; j++) {
+                       rec->session->bytes_transferred += 
thread_data[i].maps[j].bytes_transferred;
+                       rec->session->bytes_compressed  += 
thread_data[i].maps[j].bytes_compressed;
+               }
+       }
+
+       return 0;
+}
+
 static int __cmd_record(struct record *rec, int argc, const char **argv)
 {
        int err;
@@ -1903,7 +1957,7 @@ static int __cmd_record(struct record *rec, int argc, 
const char **argv)
 
        if (record__open(rec) != 0) {
                err = -1;
-               goto out_child;
+               goto out_free_threads;
        }
        session->header.env.comp_mmap_len = session->evlist->core.mmap_len;
 
@@ -2203,18 +2257,20 @@ static int __cmd_record(struct record *rec, int argc, 
const char **argv)
                goto out_child;
        }
 
-       if (!quiet)
-               fprintf(stderr, "[ perf record: Woken up %ld times to write 
data ]\n", waking);
-
        if (target__none(&rec->opts.target))
                record__synthesize_workload(rec, true);
 
 out_child:
+       record__stop_threads(rec, &waking);
+out_free_threads:
        record__free_thread_data(rec);
        evlist__finalize_ctlfd(rec->evlist);
        record__mmap_read_all(rec, true);
        record__aio_mmap_read_sync(rec);
 
+       if (!quiet)
+               fprintf(stderr, "[ perf record: Woken up %ld times to write 
data ]\n", waking);
+
        if (rec->session->bytes_transferred && rec->session->bytes_compressed) {
                ratio = 
(float)rec->session->bytes_transferred/(float)rec->session->bytes_compressed;
                session->header.env.comp_ratio = ratio + 0.5;
-- 
2.24.1