All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] perf sched timehist: Add --next option
@ 2017-03-14  1:56 Brendan Gregg
  2017-03-14 13:12 ` Arnaldo Carvalho de Melo
  2017-03-15 18:41 ` [tip:perf/core] " tip-bot for Brendan Gregg
  0 siblings, 2 replies; 4+ messages in thread
From: Brendan Gregg @ 2017-03-14  1:56 UTC (permalink / raw)
  To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Alexander Shishkin
  Cc: linux-kernel, Namhyung Kim, Brendan Gregg

The --next option shows the next task for each context switch, providing
more context for the sequence of scheduler events.

$ perf sched timehist --next | head
Samples do not have callchains.
           time    cpu  task name                       wait time  sch delay   run time
                        [tid/pid]                          (msec)     (msec)     (msec)
--------------- ------  ------------------------------  ---------  ---------  ---------
 1136374.793792 [0000]  <idle>                              0.000      0.000      0.000  next: rngd[1524]
 1136374.793801 [0000]  rngd[1524]                          0.000      0.000      0.009  next: swapper/0[0]
 1136374.794048 [0007]  <idle>                              0.000      0.000      0.000  next: yes[30884]
 1136374.794066 [0007]  yes[30884]                          0.000      0.000      0.018  next: swapper/7[0]
 1136374.794126 [0002]  <idle>                              0.000      0.000      0.000  next: rngd[1524]
 1136374.794140 [0002]  rngd[1524]                          0.325      0.006      0.013  next: swapper/2[0]
 1136374.794281 [0003]  <idle>                              0.000      0.000      0.000  next: perf[31070]

Signed-off-by: Brendan Gregg <bgregg@netflix.com>
---
 tools/perf/Documentation/perf-sched.txt |  4 ++++
 tools/perf/builtin-sched.c              | 29 ++++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index d33dedd..a092a24 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.
 
+-n::
+--next::
+	Show next task.
+
 -I::
 --idle-hist::
 	Show idle-related events only.
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index b94cf0d..fedc8f2 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -221,6 +221,7 @@ struct perf_sched {
 	unsigned int	max_stack;
 	bool		show_cpu_visual;
 	bool		show_wakeups;
+	bool		show_next;
 	bool		show_migrations;
 	bool		show_state;
 	u64		skipped_samples;
@@ -1897,14 +1898,18 @@ static char task_state_char(struct thread *thread, int state)
 }
 
 static void timehist_print_sample(struct perf_sched *sched,
+				  struct perf_evsel *evsel,
 				  struct perf_sample *sample,
 				  struct addr_location *al,
 				  struct thread *thread,
 				  u64 t, int state)
 {
 	struct thread_runtime *tr = thread__priv(thread);
+	const char *next_comm = perf_evsel__strval(evsel, sample, "next_comm");
+	const u32 next_pid = perf_evsel__intval(evsel, sample, "next_pid");
 	u32 max_cpus = sched->max_cpu + 1;
 	char tstr[64];
+	char nstr[30];
 	u64 wait_time;
 
 	timestamp__scnprintf_usec(t, tstr, sizeof(tstr));
@@ -1937,7 +1942,13 @@ static void timehist_print_sample(struct perf_sched *sched,
 	if (sched->show_state)
 		printf(" %5c ", task_state_char(thread, state));
 
-	if (sched->show_wakeups)
+	if (sched->show_next) {
+		snprintf(nstr, sizeof(nstr), "next: %s[%d]", next_comm,
+			next_pid);
+		printf(" %-*s", comm_width, nstr);
+	}
+
+	if (sched->show_wakeups && !sched->show_next)
 		printf("  %-*s", comm_width, "");
 
 	if (thread->tid == 0)
@@ -2531,7 +2542,8 @@ static int timehist_sched_change_event(struct perf_tool *tool,
 	}
 
 	if (!sched->summary_only)
-		timehist_print_sample(sched, sample, &al, thread, t, state);
+		timehist_print_sample(sched, evsel, sample, &al, thread, t,
+				      state);
 
 out:
 	if (sched->hist_time.start == 0 && t >= ptime->start)
@@ -3340,6 +3352,7 @@ int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
 	OPT_BOOLEAN('S', "with-summary", &sched.summary,
 		    "Show all syscalls and summary with statistics"),
 	OPT_BOOLEAN('w', "wakeups", &sched.show_wakeups, "Show wakeup events"),
+	OPT_BOOLEAN('n', "next", &sched.show_next, "Show next task"),
 	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"),
@@ -3437,10 +3450,16 @@ int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
 			if (argc)
 				usage_with_options(timehist_usage, timehist_options);
 		}
-		if (sched.show_wakeups && sched.summary_only) {
-			pr_err(" Error: -s and -w are mutually exclusive.\n");
+		if ((sched.show_wakeups || sched.show_next) &&
+		    sched.summary_only) {
+			pr_err(" Error: -s and -[n|w] are mutually exclusive.\n");
 			parse_options_usage(timehist_usage, timehist_options, "s", true);
-			parse_options_usage(NULL, timehist_options, "w", true);
+			if (sched.show_wakeups)
+				parse_options_usage(NULL, timehist_options, "w",
+						    true);
+			if (sched.show_next)
+				parse_options_usage(NULL, timehist_options, "n",
+						    true);
 			return -EINVAL;
 		}
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2017-03-15 18:43 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-03-14  1:56 [PATCH] perf sched timehist: Add --next option Brendan Gregg
2017-03-14 13:12 ` Arnaldo Carvalho de Melo
2017-03-15  0:39   ` Brendan Gregg
2017-03-15 18:41 ` [tip:perf/core] " tip-bot for Brendan Gregg

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.