[tip:perfcounters/core] perf sched: Account for lost events, increase default buffering

tip-bot for Ingo Molnar
2009-09-16T10:26:12Z

Commit-ID: dc02bf7178c8e2cb3d442ae19027b736d51c7dd5
Gitweb: http://git.kernel.org/tip/dc02bf7178c8e2cb3d442ae19027b736d51c7dd5
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Wed, 16 Sep 2009 13:45:00 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 16 Sep 2009 11:48:05 +0200

perf sched: Account for lost events, increase default buffering

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 | 60 ++++++++++++++++++++++++++++++--------------
tools/perf/util/event.h | 2 +-
2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index adcb563..1f0f9be 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -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",
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index fa2d4e9..2495529 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -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;