linux-kernel - Re: [PATCH 1/3] perf sched timehist: Account thread wait time separately

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Date:   Fri, 13 Jan 2017 16:35:39 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Olsa <jolsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Minchan Kim <minchan@...nel.org>,
        David Ahern <dsahern@...il.com>
Subject: Re: [PATCH 1/3] perf sched timehist: Account thread wait time
 separately

Em Fri, Jan 13, 2017 at 07:45:21PM +0900, Namhyung Kim escreveu:
> Separate thread wait time into 3 parts - sleep, iowait and preempt
> based on the prev_state of the last event.

Thanks, looks good, tested and applied,

- Arnaldo
 
> Cc: David Ahern <dsahern@...il.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/builtin-sched.c | 50 ++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 44 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 5b134b0d1ff3..0f2fdeebfd2e 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -77,6 +77,22 @@ struct sched_atom {
>  
>  #define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"
>  
> +/* task state bitmask, copied from include/linux/sched.h */
> +#define TASK_RUNNING		0
> +#define TASK_INTERRUPTIBLE	1
> +#define TASK_UNINTERRUPTIBLE	2
> +#define __TASK_STOPPED		4
> +#define __TASK_TRACED		8
> +/* in tsk->exit_state */
> +#define EXIT_DEAD		16
> +#define EXIT_ZOMBIE		32
> +#define EXIT_TRACE		(EXIT_ZOMBIE | EXIT_DEAD)
> +/* in tsk->state again */
> +#define TASK_DEAD		64
> +#define TASK_WAKEKILL		128
> +#define TASK_WAKING		256
> +#define TASK_PARKED		512
> +
>  enum thread_state {
>  	THREAD_SLEEPING = 0,
>  	THREAD_WAIT_CPU,
> @@ -216,13 +232,16 @@ struct perf_sched {
>  struct thread_runtime {
>  	u64 last_time;      /* time of previous sched in/out event */
>  	u64 dt_run;         /* run time */
> -	u64 dt_wait;        /* time between CPU access (off cpu) */
> +	u64 dt_sleep;       /* time between CPU access by sleep (off cpu) */
> +	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 ready_to_run;   /* time of wakeup */
>  
>  	struct stats run_stats;
>  	u64 total_run_time;
>  
> +	int last_state;
>  	u64 migrations;
>  };
>  
> @@ -1858,6 +1877,7 @@ static void timehist_print_sample(struct perf_sched *sched,
>  	struct thread_runtime *tr = thread__priv(thread);
>  	u32 max_cpus = sched->max_cpu + 1;
>  	char tstr[64];
> +	u64 wait_time;
>  
>  	timestamp__scnprintf_usec(t, tstr, sizeof(tstr));
>  	printf("%15s [%04d] ", tstr, sample->cpu);
> @@ -1880,7 +1900,9 @@ static void timehist_print_sample(struct perf_sched *sched,
>  
>  	printf(" %-*s ", comm_width, timehist_get_commstr(thread));
>  
> -	print_sched_time(tr->dt_wait, 6);
> +	wait_time = tr->dt_sleep + tr->dt_iowait + tr->dt_preempt;
> +	print_sched_time(wait_time, 6);
> +
>  	print_sched_time(tr->dt_delay, 6);
>  	print_sched_time(tr->dt_run, 6);
>  
> @@ -1930,8 +1952,11 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
>  					 u64 t, u64 tprev)
>  {
>  	r->dt_delay   = 0;
> -	r->dt_wait    = 0;
> +	r->dt_sleep   = 0;
> +	r->dt_iowait  = 0;
> +	r->dt_preempt = 0;
>  	r->dt_run     = 0;
> +
>  	if (tprev) {
>  		r->dt_run = t - tprev;
>  		if (r->ready_to_run) {
> @@ -1943,8 +1968,16 @@ static void timehist_update_runtime_stats(struct thread_runtime *r,
>  
>  		if (r->last_time > tprev)
>  			pr_debug("time travel: last sched out time for task > previous sched_switch event\n");
> -		else if (r->last_time)
> -			r->dt_wait = tprev - r->last_time;
> +		else if (r->last_time) {
> +			u64 wait = tprev - r->last_time;
> +
> +			if (r->last_state == TASK_RUNNING)
> +				r->dt_preempt = wait;
> +			else if (r->last_state == TASK_UNINTERRUPTIBLE)
> +				r->dt_iowait = wait;
> +			else
> +				r->dt_sleep = wait;
> +		}
>  	}
>  
>  	update_stats(&r->run_stats, r->dt_run);
> @@ -2447,8 +2480,10 @@ static int timehist_sched_change_event(struct perf_tool *tool,
>  			 * time.  we only care total run time and run stat.
>  			 */
>  			last_tr->dt_run = 0;
> -			last_tr->dt_wait = 0;
>  			last_tr->dt_delay = 0;
> +			last_tr->dt_sleep = 0;
> +			last_tr->dt_iowait = 0;
> +			last_tr->dt_preempt = 0;
>  
>  			if (itr->cursor.nr)
>  				callchain_append(&itr->callchain, &itr->cursor, t - tprev);
> @@ -2470,6 +2505,9 @@ static int timehist_sched_change_event(struct perf_tool *tool,
>  		/* time of this sched_switch event becomes last time task seen */
>  		tr->last_time = sample->time;
>  
> +		/* last state is used to determine where to account wait time */
> +		tr->last_state = perf_evsel__intval(evsel, sample, "prev_state");
> +
>  		/* sched out event for task so reset ready to run time */
>  		tr->ready_to_run = 0;
>  	}
> -- 
> 2.11.0