[PATCH] perf timehist: Handle cpu migration events

From: David Ahern
Date: Fri Nov 25 2016 - 11:29:52 EST


From: David Ahern <dsahern@xxxxxxxxx>

Add handlers for sched:sched_migrate_task event. Total number of migrations
is added to summary display and -M/--migrations can be used to show
migration events.

Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/Documentation/perf-sched.txt | 4 ++
tools/perf/builtin-sched.c | 97 ++++++++++++++++++++++++++++++++-
2 files changed, 99 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index fb9e52d65fca..121c60da03e5 100644
--- a/tools/perf/Documentation/perf-sched.txt
+++ b/tools/perf/Documentation/perf-sched.txt
@@ -128,6 +128,10 @@ OPTIONS for 'perf sched timehist'
--wakeups::
Show wakeup events.

+-M::
+--migrations::
+ Show migration events.
+
SEE ALSO
--------
linkperf:perf-record[1]
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 829468defa07..2706809bc3e4 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -203,6 +203,7 @@ struct perf_sched {
unsigned int max_stack;
bool show_cpu_visual;
bool show_wakeups;
+ bool show_migrations;
u64 skipped_samples;
};

@@ -216,6 +217,8 @@ struct thread_runtime {

struct stats run_stats;
u64 total_run_time;
+
+ u64 migrations;
};

/* per event run time data */
@@ -2175,6 +2178,87 @@ static int timehist_sched_wakeup_event(struct perf_tool *tool,
return 0;
}

+static void timehist_print_migration_event(struct perf_sched *sched,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine,
+ struct thread *migrated)
+{
+ struct thread *thread;
+ char tstr[64];
+ u32 max_cpus = sched->max_cpu + 1;
+ u32 ocpu, dcpu;
+
+ if (sched->summary_only)
+ return;
+
+ max_cpus = sched->max_cpu + 1;
+ ocpu = perf_evsel__intval(evsel, sample, "orig_cpu");
+ dcpu = perf_evsel__intval(evsel, sample, "dest_cpu");
+
+ thread = machine__findnew_thread(machine, sample->pid, sample->tid);
+ if (thread == NULL)
+ return;
+
+ if (timehist_skip_sample(sched, thread) &&
+ timehist_skip_sample(sched, migrated)) {
+ return;
+ }
+
+ timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
+ printf("%15s [%04d] ", tstr, sample->cpu);
+
+ if (sched->show_cpu_visual) {
+ u32 i;
+ char c;
+
+ printf(" ");
+ for (i = 0; i < max_cpus; ++i) {
+ c = (i == sample->cpu) ? 'm' : ' ';
+ printf("%c", c);
+ }
+ printf(" ");
+ }
+
+ printf(" %-*s ", comm_width, timehist_get_commstr(thread));
+
+ /* dt spacer */
+ printf(" %9s %9s %9s ", "", "", "");
+
+ printf("migrated: %s", timehist_get_commstr(migrated));
+ printf(" cpu %d => %d", ocpu, dcpu);
+
+ printf("\n");
+}
+
+static int timehist_migrate_task_event(struct perf_tool *tool,
+ union perf_event *event __maybe_unused,
+ struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
+ struct thread *thread;
+ struct thread_runtime *tr = NULL;
+ /* want pid of migrated task not pid in sample */
+ const u32 pid = perf_evsel__intval(evsel, sample, "pid");
+
+ thread = machine__findnew_thread(machine, 0, pid);
+ if (thread == NULL)
+ return -1;
+
+ tr = thread__get_runtime(thread);
+ if (tr == NULL)
+ return -1;
+
+ tr->migrations++;
+
+ /* show migrations if requested */
+ timehist_print_migration_event(sched, evsel, sample, machine, thread);
+
+ return 0;
+}
+
static int timehist_sched_change_event(struct perf_tool *tool,
union perf_event *event,
struct perf_evsel *evsel,
@@ -2273,6 +2357,7 @@ static void print_thread_runtime(struct thread *t,
print_sched_time(r->run_stats.max, 6);
printf(" ");
printf("%5.2f", stddev);
+ printf(" %5" PRIu64, r->migrations);
printf("\n");
}

@@ -2334,10 +2419,10 @@ static void timehist_print_summary(struct perf_sched *sched,

printf("\nRuntime summary\n");
printf("%*s parent sched-in ", comm_width, "comm");
- printf(" run-time min-run avg-run max-run stddev\n");
+ printf(" run-time min-run avg-run max-run stddev migrations\n");
printf("%*s (count) ", comm_width, "");
printf(" (msec) (msec) (msec) (msec) %%\n");
- printf("%.105s\n", graph_dotted_line);
+ printf("%.117s\n", graph_dotted_line);

machine__for_each_thread(m, show_thread_runtime, &totals);
task_count = totals.task_count;
@@ -2438,6 +2523,9 @@ static int perf_sched__timehist(struct perf_sched *sched)
{ "sched:sched_wakeup", timehist_sched_wakeup_event, },
{ "sched:sched_wakeup_new", timehist_sched_wakeup_event, },
};
+ const struct perf_evsel_str_handler migrate_handlers[] = {
+ { "sched:sched_migrate_task", timehist_migrate_task_event, },
+ };
struct perf_data_file file = {
.path = input_name,
.mode = PERF_DATA_MODE_READ,
@@ -2485,6 +2573,10 @@ static int perf_sched__timehist(struct perf_sched *sched)
if (!perf_session__has_traces(session, "record -R"))
goto out;

+ if (sched->show_migrations &&
+ perf_session__set_tracepoints_handlers(session, migrate_handlers))
+ goto out;
+
/* pre-allocate struct for per-CPU idle stats */
sched->max_cpu = session->header.env.nr_cpus_online;
if (sched->max_cpu == 0)
@@ -2881,6 +2973,7 @@ 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('M', "migrations", &sched.show_migrations, "Show migration events"),
OPT_BOOLEAN('V', "cpu-visual", &sched.show_cpu_visual, "Add CPU visual"),
OPT_PARENT(sched_options)
};
--
2.7.4 (Apple Git-66)