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Commit 292c4a8f authored by Brendan Gregg's avatar Brendan Gregg Committed by Arnaldo Carvalho de Melo
Browse files

perf sched timehist: Add --next option 



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  waittime schdelay run time
                 [tid/pid]     (msec) (msec) (msec)
  ---------- --- ---------- --------- ------ -----
  374.793792 [0] <idle>         0.000  0.000 0.000 next: rngd[1524]
  374.793801 [0] rngd[1524]     0.000  0.000 0.009 next: swapper/0[0]
  374.794048 [7] <idle>         0.000  0.000 0.000 next: yes[30884]
  374.794066 [7] yes[30884]     0.000  0.000 0.018 next: swapper/7[0]
  374.794126 [2] <idle>         0.000  0.000 0.000 next: rngd[1524]
  374.794140 [2] rngd[1524]     0.325  0.006 0.013 next: swapper/2[0]
  374.794281 [3] <idle>         0.000  0.000 0.000 next: perf[31070]

Signed-off-by: default avatarBrendan Gregg <bgregg@netflix.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1489456589-32555-1-git-send-email-bgregg@netflix.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d890a98c

tools/perf/Documentation/perf-sched.txt

+4 −0
Original line number Diff line number Diff line
@@ -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.

tools/perf/builtin-sched.c

+20 −5
Original line number Diff line number Diff line
@@ -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 +1942,12 @@ 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 +2541,7 @@ 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)
@@ -3341,6 +3351,7 @@ 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"),
@@ -3438,10 +3449,14 @@ 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);

			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;

		}