mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-14 10:19:08 +08:00
perf sched timehist: Add pre-migration wait time option
pre-migration wait time is the time that a task unnecessarily spends
on the runqueue of a CPU but doesn't get switched-in there. In terms
of tracepoints, it is the time between sched:sched_wakeup and
sched:sched_migrate_task.
Let's say a task woke up on CPU2, then it got migrated to CPU4 and
then it's switched-in to CPU4. So, here pre-migration wait time is
time that it was waiting on runqueue of CPU2 after it is woken up.
The general pattern for pre-migration to occur is:
sched:sched_wakeup
sched:sched_migrate_task
sched:sched_switch
The sched:sched_waking event is used to capture the wakeup time,
as it aligns with the existing code and only introduces a negligible
time difference.
pre-migrations are generally not useful and it increases migrations.
This metric would be helpful in testing patches mainly related to wakeup
and load-balancer code paths as better wakeup logic would choose an
optimal CPU where task would be switched-in and thereby reducing pre-
migrations.
The sample output(s) when -P or --pre-migrations is used:
=================
time cpu task name wait time sch delay run time pre-mig time
[tid/pid] (msec) (msec) (msec) (msec)
--------------- ------ ------------------------------ --------- --------- --------- ---------
38456.720806 [0001] schbench[28634/28574] 4.917 4.768 1.004 0.000
38456.720810 [0001] rcu_preempt[18] 3.919 0.003 0.004 0.000
38456.721800 [0006] schbench[28779/28574] 23.465 23.465 1.999 0.000
38456.722800 [0002] schbench[28773/28574] 60.371 60.237 3.955 60.197
38456.722806 [0001] schbench[28634/28574] 0.004 0.004 1.996 0.000
38456.722811 [0001] rcu_preempt[18] 1.996 0.005 0.005 0.000
38456.723800 [0000] schbench[28833/28574] 4.000 4.000 3.999 0.000
38456.723800 [0004] schbench[28762/28574] 42.951 42.839 3.999 39.867
38456.723802 [0007] schbench[28812/28574] 43.947 43.817 3.999 40.866
38456.723804 [0001] schbench[28587/28574] 7.935 7.822 0.993 0.000
Signed-off-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Link: https://lore.kernel.org/r/20241004170756.18064-1-vineethr@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Madadi Vineeth Reddy
committed by
Namhyung Kim
Namhyung Kim
parent
af3902bfc1
commit
cd912ab3b6
@@ -221,6 +221,14 @@ OPTIONS for 'perf sched timehist'
|
||||
priorities are specified with -: 120-129. A combination of both can also be
|
||||
provided: 0,120-129.
|
||||
|
||||
-P::
|
||||
--pre-migrations::
|
||||
Show pre-migration wait time. pre-migration wait time is the time spent
|
||||
by a task waiting on a runqueue but not getting the chance to run there
|
||||
and is migrated to a different runqueue where it is finally run. This
|
||||
time between sched_wakeup and migrate_task is the pre-migration wait
|
||||
time.
|
||||
|
||||
OPTIONS for 'perf sched replay'
|
||||
------------------------------
|
||||
|
||||
|
||||
@@ -225,6 +225,7 @@ struct perf_sched {
|
||||
bool show_wakeups;
|
||||
bool show_next;
|
||||
bool show_migrations;
|
||||
bool pre_migrations;
|
||||
bool show_state;
|
||||
bool show_prio;
|
||||
u64 skipped_samples;
|
||||
@@ -244,7 +245,9 @@ struct thread_runtime {
|
||||
u64 dt_iowait; /* time between CPU access by iowait (off cpu) */
|
||||
u64 dt_preempt; /* time between CPU access by preempt (off cpu) */
|
||||
u64 dt_delay; /* time between wakeup and sched-in */
|
||||
u64 dt_pre_mig; /* time between migration and wakeup */
|
||||
u64 ready_to_run; /* time of wakeup */
|
||||
u64 migrated; /* time when a thread is migrated */
|
||||
|
||||
struct stats run_stats;
|
||||
u64 total_run_time;
|
||||
@@ -252,6 +255,7 @@ struct thread_runtime {
|
||||
u64 total_iowait_time;
|
||||
u64 total_preempt_time;
|
||||
u64 total_delay_time;
|
||||
u64 total_pre_mig_time;
|
||||
|
||||
char last_state;
|
||||
|
||||
@@ -2073,14 +2077,15 @@ static void timehist_header(struct perf_sched *sched)
|
||||
printf(" ");
|
||||
}
|
||||
|
||||
if (sched->show_prio) {
|
||||
printf(" %-*s %-*s %9s %9s %9s",
|
||||
comm_width, "task name", MAX_PRIO_STR_LEN, "prio",
|
||||
"wait time", "sch delay", "run time");
|
||||
} else {
|
||||
printf(" %-*s %9s %9s %9s", comm_width,
|
||||
"task name", "wait time", "sch delay", "run time");
|
||||
}
|
||||
printf(" %-*s", comm_width, "task name");
|
||||
|
||||
if (sched->show_prio)
|
||||
printf(" %-*s", MAX_PRIO_STR_LEN, "prio");
|
||||
|
||||
printf(" %9s %9s %9s", "wait time", "sch delay", "run time");
|
||||
|
||||
if (sched->pre_migrations)
|
||||
printf(" %9s", "pre-mig time");
|
||||
|
||||
if (sched->show_state)
|
||||
printf(" %s", "state");
|
||||
@@ -2095,17 +2100,15 @@ static void timehist_header(struct perf_sched *sched)
|
||||
if (sched->show_cpu_visual)
|
||||
printf(" %*s ", ncpus, "");
|
||||
|
||||
if (sched->show_prio) {
|
||||
printf(" %-*s %-*s %9s %9s %9s",
|
||||
comm_width, "[tid/pid]", MAX_PRIO_STR_LEN, "",
|
||||
"(msec)", "(msec)", "(msec)");
|
||||
} else {
|
||||
printf(" %-*s %9s %9s %9s", comm_width,
|
||||
"[tid/pid]", "(msec)", "(msec)", "(msec)");
|
||||
}
|
||||
printf(" %-*s", comm_width, "[tid/pid]");
|
||||
|
||||
if (sched->show_state)
|
||||
printf(" %5s", "");
|
||||
if (sched->show_prio)
|
||||
printf(" %-*s", MAX_PRIO_STR_LEN, "");
|
||||
|
||||
printf(" %9s %9s %9s", "(msec)", "(msec)", "(msec)");
|
||||
|
||||
if (sched->pre_migrations)
|
||||
printf(" %9s", "(msec)");
|
||||
|
||||
printf("\n");
|
||||
|
||||
@@ -2117,15 +2120,15 @@ static void timehist_header(struct perf_sched *sched)
|
||||
if (sched->show_cpu_visual)
|
||||
printf(" %.*s ", ncpus, graph_dotted_line);
|
||||
|
||||
if (sched->show_prio) {
|
||||
printf(" %.*s %.*s %.9s %.9s %.9s",
|
||||
comm_width, graph_dotted_line, MAX_PRIO_STR_LEN, graph_dotted_line,
|
||||
graph_dotted_line, graph_dotted_line, graph_dotted_line);
|
||||
} else {
|
||||
printf(" %.*s %.9s %.9s %.9s", comm_width,
|
||||
graph_dotted_line, graph_dotted_line, graph_dotted_line,
|
||||
graph_dotted_line);
|
||||
}
|
||||
printf(" %.*s", comm_width, graph_dotted_line);
|
||||
|
||||
if (sched->show_prio)
|
||||
printf(" %.*s", MAX_PRIO_STR_LEN, graph_dotted_line);
|
||||
|
||||
printf(" %.9s %.9s %.9s", graph_dotted_line, graph_dotted_line, graph_dotted_line);
|
||||
|
||||
if (sched->pre_migrations)
|
||||
printf(" %.9s", graph_dotted_line);
|
||||
|
||||
if (sched->show_state)
|
||||
printf(" %.5s", graph_dotted_line);
|
||||
@@ -2180,6 +2183,8 @@ static void timehist_print_sample(struct perf_sched *sched,
|
||||
|
||||
print_sched_time(tr->dt_delay, 6);
|
||||
print_sched_time(tr->dt_run, 6);
|
||||
if (sched->pre_migrations)
|
||||
print_sched_time(tr->dt_pre_mig, 6);
|
||||
|
||||
if (sched->show_state)
|
||||
printf(" %5c ", thread__tid(thread) == 0 ? 'I' : state);
|
||||
@@ -2217,18 +2222,21 @@ out:
|
||||
* last_time = time of last sched change event for current task
|
||||
* (i.e, time process was last scheduled out)
|
||||
* ready_to_run = time of wakeup for current task
|
||||
* migrated = time of task migration to another CPU
|
||||
*
|
||||
* -----|------------|------------|------------|------
|
||||
* last ready tprev t
|
||||
* -----|-------------|-------------|-------------|-------------|-----
|
||||
* last ready migrated tprev t
|
||||
* time to run
|
||||
*
|
||||
* |-------- dt_wait --------|
|
||||
* |- dt_delay -|-- dt_run --|
|
||||
* |---------------- dt_wait ----------------|
|
||||
* |--------- dt_delay ---------|-- dt_run --|
|
||||
* |- dt_pre_mig -|
|
||||
*
|
||||
* dt_run = run time of current task
|
||||
* dt_wait = time between last schedule out event for task and tprev
|
||||
* represents time spent off the cpu
|
||||
* dt_delay = time between wakeup and schedule-in of task
|
||||
* dt_run = run time of current task
|
||||
* dt_wait = time between last schedule out event for task and tprev
|
||||
* represents time spent off the cpu
|
||||
* dt_delay = time between wakeup and schedule-in of task
|
||||
* dt_pre_mig = time between wakeup and migration to another CPU
|
||||
*/
|
||||
|
||||
static void timehist_update_runtime_stats(struct thread_runtime *r,
|
||||
@@ -2239,6 +2247,7 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
|
||||
r->dt_iowait = 0;
|
||||
r->dt_preempt = 0;
|
||||
r->dt_run = 0;
|
||||
r->dt_pre_mig = 0;
|
||||
|
||||
if (tprev) {
|
||||
r->dt_run = t - tprev;
|
||||
@@ -2247,6 +2256,9 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
|
||||
pr_debug("time travel: wakeup time for task > previous sched_switch event\n");
|
||||
else
|
||||
r->dt_delay = tprev - r->ready_to_run;
|
||||
|
||||
if ((r->migrated > r->ready_to_run) && (r->migrated < tprev))
|
||||
r->dt_pre_mig = r->migrated - r->ready_to_run;
|
||||
}
|
||||
|
||||
if (r->last_time > tprev)
|
||||
@@ -2270,6 +2282,7 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
|
||||
r->total_sleep_time += r->dt_sleep;
|
||||
r->total_iowait_time += r->dt_iowait;
|
||||
r->total_preempt_time += r->dt_preempt;
|
||||
r->total_pre_mig_time += r->dt_pre_mig;
|
||||
}
|
||||
|
||||
static bool is_idle_sample(struct perf_sample *sample,
|
||||
@@ -2683,9 +2696,13 @@ static int timehist_migrate_task_event(const struct perf_tool *tool,
|
||||
return -1;
|
||||
|
||||
tr->migrations++;
|
||||
tr->migrated = sample->time;
|
||||
|
||||
/* show migrations if requested */
|
||||
timehist_print_migration_event(sched, evsel, sample, machine, thread);
|
||||
if (sched->show_migrations) {
|
||||
timehist_print_migration_event(sched, evsel, sample,
|
||||
machine, thread);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
@@ -2836,11 +2853,13 @@ out:
|
||||
/* last state is used to determine where to account wait time */
|
||||
tr->last_state = state;
|
||||
|
||||
/* sched out event for task so reset ready to run time */
|
||||
/* sched out event for task so reset ready to run time and migrated time */
|
||||
if (state == 'R')
|
||||
tr->ready_to_run = t;
|
||||
else
|
||||
tr->ready_to_run = 0;
|
||||
|
||||
tr->migrated = 0;
|
||||
}
|
||||
|
||||
evsel__save_time(evsel, sample->time, sample->cpu);
|
||||
@@ -3280,8 +3299,8 @@ static int perf_sched__timehist(struct perf_sched *sched)
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (sched->show_migrations &&
|
||||
perf_session__set_tracepoints_handlers(session, migrate_handlers))
|
||||
if ((sched->show_migrations || sched->pre_migrations) &&
|
||||
perf_session__set_tracepoints_handlers(session, migrate_handlers))
|
||||
goto out;
|
||||
|
||||
/* pre-allocate struct for per-CPU idle stats */
|
||||
@@ -3823,6 +3842,7 @@ int cmd_sched(int argc, const char **argv)
|
||||
OPT_BOOLEAN(0, "show-prio", &sched.show_prio, "Show task priority"),
|
||||
OPT_STRING(0, "prio", &sched.prio_str, "prio",
|
||||
"analyze events only for given task priority(ies)"),
|
||||
OPT_BOOLEAN('P', "pre-migrations", &sched.pre_migrations, "Show pre-migration wait time"),
|
||||
OPT_PARENT(sched_options)
|
||||
};
|
||||
|
||||
|
||||
Reference in New Issue
Block a user