linux-kernel - Re: [PATCH 06/10] perf sched timehist: Introduce struct idle_time

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Message-ID: <21a35a2f-2cdb-78d1-a42d-078f267fdc1c@gmail.com>
Date:   Mon, 5 Dec 2016 20:07:09 -0800
From:   David Ahern <dsahern@...il.com>
To:     Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Olsa <jolsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <andi@...stfloor.org>,
        Minchan Kim <minchan@...nel.org>
Subject: Re: [PATCH 06/10] perf sched timehist: Introduce struct
 idle_time_data

On 12/5/16 7:40 PM, Namhyung Kim wrote:
> The struct idle_time_data is to keep idle stats with callchains entering
> to the idle task.  The normal thread_runtime calculation is done
> transparently since it extends the struct thread_runtime.
> 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/builtin-sched.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 26efa99567b8..d3ee814ce77f 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -230,6 +230,15 @@ struct evsel_runtime {
>  	u32 ncpu;       /* highest cpu slot allocated */
>  };
>  
> +/* per cpu idle time data */
> +struct idle_thread_runtime {
> +	struct thread_runtime tr;
> +	struct thread *last_thread;
> +	struct rb_root sorted_root;
> +	struct callchain_root callchain;
> +	struct callchain_cursor cursor;
> +};
> +
>  /* track idle times per cpu */
>  static struct thread **idle_threads;
>  static int idle_max_cpu;
> @@ -2009,11 +2018,22 @@ static int init_idle_threads(int ncpu)
>  
>  	/* allocate the actual thread struct if needed */
>  	for (i = 0; i < ncpu; ++i) {
> +		struct idle_thread_runtime *itr;
> +
>  		idle_threads[i] = thread__new(0, 0);
>  		if (idle_threads[i] == NULL)
>  			return -ENOMEM;
>  
>  		thread__set_comm(idle_threads[i], idle_comm, 0);
> +
> +		itr = zalloc(sizeof(*itr));
> +		if (itr == NULL)
> +			return -ENOMEM;
> +
> +		init_stats(&itr->tr.run_stats);
> +		callchain_init(&itr->callchain);
> +		callchain_cursor_reset(&itr->cursor);
> +		thread__set_priv(idle_threads[i], itr);

perhaps the common lines above should be put into init_idle_thread() and called in both places to init a single idle thread instance.


>  	}
>  
>  	return 0;
> @@ -2060,8 +2080,19 @@ static struct thread *get_idle_thread(int cpu)
>  		idle_threads[cpu] = thread__new(0, 0);
>  
>  		if (idle_threads[cpu]) {
> +			struct idle_thread_runtime *itr;
> +
>  			idle_threads[cpu]->tid = 0;
>  			thread__set_comm(idle_threads[cpu], idle_comm, 0);
> +
> +			itr = zalloc(sizeof(*itr));
> +			if (itr == NULL)
> +				return NULL;
> +
> +			init_stats(&itr->tr.run_stats);
> +			callchain_init(&itr->callchain);
> +			callchain_cursor_reset(&itr->cursor);
> +			thread__set_priv(idle_threads[cpu], itr);
>  		}
>  	}
>  
>