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Groups > linux.kernel > #1600817

[PATCH 14/19] perf sched timehist: Add --next option

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 14/19] perf sched timehist: Add --next option
Date 2017-03-14 20:00 +0100
Message-ID <tkZPQ-4ju-41@gated-at.bofh.it> (permalink)
References <tkZPP-4ju-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Brendan Gregg <bgregg@netflix.com>

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: Brendan Gregg <bgregg@netflix.com>
Tested-by: Arnaldo 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: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-sched.txt |  4 ++++
 tools/perf/builtin-sched.c              | 25 ++++++++++++++++++++-----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index d33deddb0146..a092a2499e8f 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 16170e9b47e6..b92c4d97192c 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 +1942,12 @@ 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);
-			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;
 		}
 
-- 
2.9.3

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[GIT PULL 00/19] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 17/19] perf powerpc: Choose local entry point with kretprobes Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 12/19] perf script: Add script print support for namespace events Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 16/19] perf kretprobes: Offset from reloc_sym if kernel supports it Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 04/19] perf tools: Missing c2c command in command-list Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 07/19] perf report: Document +field style argument support for --field option Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 05/19] perf tools: Ignore generated files pmu-events/{jevents,pmu-events.c} for git Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 06/19] perf sort: Fix segfault with basic block 'cycles' sort dimension Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 19/19] kprobes: Convert kprobe_exceptions_notify to use NOKPROBE_SYMBOL Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 14/19] perf sched timehist: Add --next option Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 13/19] perf tools: Add 'cgroup_id' sort order keyword Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 03/19] perf c2c: Fix display bug when using pipe Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 01/19] perf report: Hide tip message when -q option is given Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 02/19] perf c2c: Clarify help message of --stats option Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 18/19] doc: trace/kprobes: add information about NOKPROBE_SYMBOL Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 10/19] perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 08/19] perf hists browser: Fix typo in function switch_data_file Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  [PATCH 15/19] perf probe: Factor out the ftrace README scanning Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-03-14 20:00 +0100
  Re: [GIT PULL 00/19] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2017-03-15 19:40 +0100

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