[tip:perf/urgent] perf sched timehist: Add -I/--idle-hist option

tip-bot for Namhyung Kim
2016-12-20T19:22:40Z

Commit-ID: 07235f84ece6b66f43334881806aad3467cf3d84
Gitweb: http://git.kernel.org/tip/07235f84ece6b66f43334881806aad3467cf3d84
Author: Namhyung Kim <namhyung@kernel.org>
AuthorDate: Thu, 8 Dec 2016 23:47:54 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 15 Dec 2016 16:25:45 -0300

perf sched timehist: Add -I/--idle-hist option

The --idle-hist option is to analyze system idle state so which process
makes cpu to go idle. If this option is specified, non-idle events will
be skipped and processes switching to/from idle will be shown.

This option is mostly useful when used with --summary(-only) option. In
the idle-time summary view, idle time is accounted to previous thread
which is run before idle task.

The example output looks like following:

Idle-time summary
comm parent sched-out idle-time min-idle avg-idle max-idle stddev migrations
(count) (msec) (msec) (msec) (msec) %
--------------------------------------------------------------------------------------------
rcu_preempt[7] 2 95 550.872 0.011 5.798 23.146 7.63 0
migration/1[16] 2 1 15.558 15.558 15.558 15.558 0.00 0
khugepaged[39] 2 1 3.062 3.062 3.062 3.062 0.00 0
kworker/0:1H[124] 2 2 4.728 0.611 2.364 4.116 74.12 0
systemd-journal[167] 1 1 4.510 4.510 4.510 4.510 0.00 0
kworker/u16:3[558] 2 13 74.737 0.080 5.749 12.960 21.96 0
irq/34-iwlwifi[628] 2 21 118.403 0.032 5.638 23.990 24.00 0
kworker/u17:0[673] 2 1 3.523 3.523 3.523 3.523 0.00 0
dbus-daemon[722] 1 1 6.743 6.743 6.743 6.743 0.00 0
ifplugd[741] 1 1 58.826 58.826 58.826 58.826 0.00 0
wpa_supplicant[1490] 1 1 13.302 13.302 13.302 13.302 0.00 0
wpa_actiond[1492] 1 2 4.064 0.168 2.032 3.896 91.72 0
dockerd[1500] 1 1 0.055 0.055 0.055 0.055 0.00 0
...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-6-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-2-namhyung@kernel.org
[ Merged fix sent by Namhyumg, as posted in the second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-sched.txt | 4 +++
tools/perf/builtin-sched.c | 46 +++++++++++++++++++++++++++++----
2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index 7775b1e..7617396 100644
--- a/tools/perf/Documentation/perf-sched.txt
+++ b/tools/perf/Documentation/perf-sched.txt
@@ -132,6 +132,10 @@ OPTIONS for 'perf sched timehist'
--migrations::
Show migration events.

+-I::
+--idle-hist::
+ Show idle-related events only.
+
--time::
Only analyze samples within given time window: <start>,<stop>. Times
have the format seconds.microseconds. If start is not given (i.e., time
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index c8e7848..0b14265 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2421,7 +2421,36 @@ static int timehist_sched_change_event(struct perf_tool *tool,
t = ptime->end;
}

- timehist_update_runtime_stats(tr, t, tprev);
+ if (!sched->idle_hist || thread->tid == 0) {
+ timehist_update_runtime_stats(tr, t, tprev);
+
+ if (sched->idle_hist) {
+ struct idle_thread_runtime *itr = (void *)tr;
+ struct thread_runtime *last_tr;
+
+ BUG_ON(thread->tid != 0);
+
+ if (itr->last_thread == NULL)
+ goto out;
+
+ /* add current idle time as last thread's runtime */
+ last_tr = thread__get_runtime(itr->last_thread);
+ if (last_tr == NULL)
+ goto out;
+
+ timehist_update_runtime_stats(last_tr, t, tprev);
+ /*
+ * remove delta time of last thread as it's not updated
+ * and otherwise it will show an invalid value next
+ * time. we only care total run time and run stat.
+ */
+ last_tr->dt_run = 0;
+ last_tr->dt_wait = 0;
+ last_tr->dt_delay = 0;
+
+ itr->last_thread = NULL;
+ }
+ }

if (!sched->summary_only)
timehist_print_sample(sched, sample, &al, thread, t);
@@ -2543,9 +2572,15 @@ static void timehist_print_summary(struct perf_sched *sched,
if (comm_width < 30)
comm_width = 30;

- printf("\nRuntime summary\n");
- printf("%*s parent sched-in ", comm_width, "comm");
- printf(" run-time min-run avg-run max-run stddev migrations\n");
+ if (sched->idle_hist) {
+ printf("\nIdle-time summary\n");
+ printf("%*s parent sched-out ", comm_width, "comm");
+ printf(" idle-time min-idle avg-idle max-idle stddev migrations\n");
+ } else {
+ printf("\nRuntime summary\n");
+ printf("%*s parent sched-in ", comm_width, "comm");
+ printf(" run-time min-run avg-run max-run stddev migrations\n");
+ }
printf("%*s (count) ", comm_width, "");
printf(" (msec) (msec) (msec) (msec) %%\n");
printf("%.117s\n", graph_dotted_line);
@@ -2561,7 +2596,7 @@ static void timehist_print_summary(struct perf_sched *sched,
printf("<no terminated tasks>\n");

/* CPU idle stats not tracked when samples were skipped */
- if (sched->skipped_samples)
+ if (sched->skipped_samples && !sched->idle_hist)
return;

printf("\nIdle stats:\n");
@@ -3107,6 +3142,7 @@ int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
OPT_BOOLEAN('w', "wakeups", &sched.show_wakeups, "Show wakeup events"),
OPT_BOOLEAN('M', "migrations", &sched.show_migrations, "Show migration events"),
OPT_BOOLEAN('V', "cpu-visual", &sched.show_cpu_visual, "Add CPU visual"),
+ OPT_BOOLEAN('I', "idle-hist", &sched.idle_hist, "Show idle events only"),
OPT_STRING(0, "time", &sched.time_str, "str",
"Time span for analysis (start,stop)"),
OPT_PARENT(sched_options)