perf sched: Account for lost events, increase default buffering
Ingo Molnar [Wed, 16 Sep 2009 11:45:00 +0000 (13:45 +0200)]
Output such lost event and state machine weirdness stats:

   TOTAL:                |  14974.910 ms |    46384 |
  ---------------------------------------------------
   INFO: 8.865% lost events (19132 out of 215819, in 8 chunks)
   INFO: 0.198% state machine bugs (49 out of 24708) (due to lost events?)

And increase buffering to -m 1024 (4 MB) by default. Since we
use output multiplexing that kind of space is needed.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-sched.c
tools/perf/util/event.h

index adcb563..1f0f9be 100644 (file)
@@ -117,7 +117,11 @@ static u64                 run_avg;
 
 static unsigned long           replay_repeat = 10;
 static unsigned long           nr_timestamps;
-static unsigned long           unordered_timestamps;
+static unsigned long           nr_unordered_timestamps;
+static unsigned long           nr_state_machine_bugs;
+static unsigned long           nr_events;
+static unsigned long           nr_lost_chunks;
+static unsigned long           nr_lost_events;
 
 #define TASK_STATE_TO_CHAR_STR "RSDTtZX"
 
@@ -668,14 +672,14 @@ process_comm_event(event_t *event, unsigned long offset, unsigned long head)
 
        thread = threads__findnew(event->comm.pid, &threads, &last_match);
 
-       dump_printf("%p [%p]: PERF_EVENT_COMM: %s:%d\n",
+       dump_printf("%p [%p]: perf_event_comm: %s:%d\n",
                (void *)(offset + head),
                (void *)(long)(event->header.size),
                event->comm.comm, event->comm.pid);
 
        if (thread == NULL ||
            thread__set_comm(thread, event->comm.comm)) {
-               dump_printf("problem processing PERF_EVENT_COMM, skipping event.\n");
+               dump_printf("problem processing perf_event_comm, skipping event.\n");
                return -1;
        }
        total_comm++;
@@ -1168,14 +1172,12 @@ latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
 
        atom = list_entry(atoms->work_list.prev, struct work_atom, list);
 
-       if (atom->state != THREAD_SLEEPING) {
-               printf("boo2\n");
-               return;
-       }
+       if (atom->state != THREAD_SLEEPING)
+               nr_state_machine_bugs++;
 
        nr_timestamps++;
        if (atom->sched_out_time > timestamp) {
-               unordered_timestamps++;
+               nr_unordered_timestamps++;
                return;
        }
 
@@ -1214,7 +1216,7 @@ static void output_lat_thread(struct work_atoms *work_list)
 
        avg = work_list->total_lat / work_list->nb_atoms;
 
-       printf("|%9.3f ms |%9llu | avg:%9.3f ms | max:%9.3f ms |\n",
+       printf("|%11.3f ms |%9llu | avg:%9.3f ms | max:%9.3f ms |\n",
              (double)work_list->total_runtime / 1e6,
                 work_list->nb_atoms, (double)avg / 1e6,
                 (double)work_list->max_lat / 1e6);
@@ -1359,9 +1361,9 @@ static void __cmd_lat(void)
        read_events();
        sort_lat();
 
-       printf("\n ---------------------------------------------------------------------------------------\n");
-       printf("  Task                  |  Runtime ms | Switches | Average delay ms | Maximum delay ms |\n");
-       printf(" ---------------------------------------------------------------------------------------\n");
+       printf("\n -----------------------------------------------------------------------------------------\n");
+       printf("  Task                  |   Runtime ms  | Switches | Average delay ms | Maximum delay ms |\n");
+       printf(" -----------------------------------------------------------------------------------------\n");
 
        next = rb_first(&sorted_atom_root);
 
@@ -1373,18 +1375,32 @@ static void __cmd_lat(void)
                next = rb_next(next);
        }
 
-       printf(" ---------------------------------------------------------------------------------------\n");
-       printf("  TOTAL:                |%9.3f ms |%9Ld |",
+       printf(" -----------------------------------------------------------------------------------------\n");
+       printf("  TOTAL:                |%11.3f ms |%9Ld |\n",
                (double)all_runtime/1e6, all_count);
 
-       if (unordered_timestamps && nr_timestamps) {
-               printf(" INFO: %.2f%% unordered events.\n",
-                       (double)unordered_timestamps/(double)nr_timestamps*100.0);
+       printf(" ---------------------------------------------------\n");
+       if (nr_unordered_timestamps && nr_timestamps) {
+               printf("  INFO: %.3f%% unordered timestamps (%ld out of %ld)\n",
+                       (double)nr_unordered_timestamps/(double)nr_timestamps*100.0,
+                       nr_unordered_timestamps, nr_timestamps);
        } else {
+       }
+       if (nr_lost_events && nr_events) {
+               printf("  INFO: %.3f%% lost events (%ld out of %ld, in %ld chunks)\n",
+                       (double)nr_lost_events/(double)nr_events*100.0,
+                       nr_lost_events, nr_events, nr_lost_chunks);
+       }
+       if (nr_state_machine_bugs && nr_timestamps) {
+               printf("  INFO: %.3f%% state machine bugs (%ld out of %ld)",
+                       (double)nr_state_machine_bugs/(double)nr_timestamps*100.0,
+                       nr_state_machine_bugs, nr_timestamps);
+               if (nr_lost_events)
+                       printf(" (due to lost events?)");
                printf("\n");
        }
+       printf("\n");
 
-       printf(" -------------------------------------------------\n\n");
 }
 
 static struct trace_sched_handler *trace_handler;
@@ -1585,8 +1601,13 @@ process_event(event_t *event, unsigned long offset, unsigned long head)
 {
        trace_event(event);
 
+       nr_events++;
        switch (event->header.type) {
-       case PERF_EVENT_MMAP ... PERF_EVENT_LOST:
+       case PERF_EVENT_MMAP:
+               return 0;
+       case PERF_EVENT_LOST:
+               nr_lost_chunks++;
+               nr_lost_events += event->lost.lost;
                return 0;
 
        case PERF_EVENT_COMM:
@@ -1768,6 +1789,7 @@ static const char *record_args[] = {
        "-R",
        "-M",
        "-f",
+       "-m", "1024",
        "-c", "1",
        "-e", "sched:sched_switch:r",
        "-e", "sched:sched_stat_wait:r",
index fa2d4e9..2495529 100644 (file)
@@ -52,7 +52,7 @@ struct lost_event {
  */
 struct read_event {
        struct perf_event_header header;
-       u32 pid,tid;
+       u32 pid, tid;
        u64 value;
        u64 time_enabled;
        u64 time_running;