Re: [PATCH] perf sched map: Add command-name option to filter the output map

[Namhyung Kim]

Hello,

Sorry for the late reply.

On Wed, Apr 17, 2024 at 08:55:21PM +0530, Madadi Vineeth Reddy wrote:
> By default, perf sched map prints sched-in events for all the tasks
> which may not be required all the time as it prints lot of symbols
> and rows to the terminal.
> 
> With --command-name option, one could specify the specific command
> for which the map has to be shown. This would help in analyzing the
> CPU usage patterns easier for that specific command. Since multiple
> PID's might have the same command name, using command-name filter
> would be more useful for debugging.
> 
> For other tasks, instead of printing the symbol, ** is printed and
> the same . is used to represent idle. ** is used instead of symbol
> for other tasks because it helps in clear visualization of command
> of interest and secondly the symbol itself doesn't mean anything
> because the sched-in of that symbol will not be printed(first sched-in
> contains pid and the corresponding symbol).
> 
> 6.8.0
> ======
>   *A0                   213864.670142 secs A0 => migration/0:18
>   *.                    213864.670148 secs .  => swapper:0
>    .  *B0               213864.670217 secs B0 => migration/1:21
>    .  *.                213864.670223 secs
>    .   .  *C0           213864.670247 secs C0 => migration/2:26
>    .   .  *.            213864.670252 secs
> 
> 6.8.0 + patch (--command-name = schbench)
> =============
>    **  .   ** *A0       213864.671055 secs A0 => schbench:104834
>   *B0  .   .   A0       213864.671156 secs B0 => schbench:104835
>   *C0  .   .   A0       213864.671187 secs C0 => schbench:104836
>   *D0  .   .   A0       213864.671219 secs D0 => schbench:104837
>   *E0  .   .   A0       213864.671250 secs E0 => schbench:104838
>    E0  .  *D0  A0
> 
> This helps in visualizing how a benchmark like schbench is spread over
> the available cpus while also knowing which cpus are idle(.) and which
> are not(**). This will be more useful as number of CPUs increase.

Yeah I think this is good!  Thanks for working on this.

But I guess people want to see when the tasks were sched out as well.
Can you please add that too?

> 
> Signed-off-by: Madadi Vineeth Reddy <vineethr@xxxxxxxxxxxxx>
> ---
>  tools/perf/Documentation/perf-sched.txt |  4 ++++
>  tools/perf/builtin-sched.c              | 17 ++++++++++++++---
>  2 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
> index 5fbe42bd599b..b04a37560935 100644
> --- a/tools/perf/Documentation/perf-sched.txt
> +++ b/tools/perf/Documentation/perf-sched.txt
> @@ -94,6 +94,10 @@ OPTIONS for 'perf sched map'
>  --color-pids::
>  	Highlight the given pids.
>  
> +--command-name::
> +	Map output only for the given command name.
> +	(** indicates other tasks while . is idle).

Probably we can support multiple names in CSV.

Thanks,
Namhyung


> +
>  OPTIONS for 'perf sched timehist'
>  ---------------------------------
>  -k::
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 0fce7d8986c0..e60836da53e5 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -156,6 +156,7 @@ struct perf_sched_map {
>  	const char		*color_pids_str;
>  	struct perf_cpu_map	*color_cpus;
>  	const char		*color_cpus_str;
> +	const char		*command;
>  	struct perf_cpu_map	*cpus;
>  	const char		*cpus_str;
>  };
> @@ -1594,8 +1595,6 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  
>  	sched->curr_thread[this_cpu.cpu] = thread__get(sched_in);
>  
> -	printf("  ");
> -
>  	new_shortname = 0;
>  	if (!tr->shortname[0]) {
>  		if (!strcmp(thread__comm_str(sched_in), "swapper")) {
> @@ -1605,7 +1604,8 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  			 */
>  			tr->shortname[0] = '.';
>  			tr->shortname[1] = ' ';
> -		} else {
> +		} else if (!sched->map.command || !strcmp(thread__comm_str(sched_in),
> +								sched->map.command)) {
>  			tr->shortname[0] = sched->next_shortname1;
>  			tr->shortname[1] = sched->next_shortname2;
>  
> @@ -1618,10 +1618,18 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  				else
>  					sched->next_shortname2 = '0';
>  			}
> +		} else {
> +			tr->shortname[0] = '*';
> +			tr->shortname[1] = '*';
>  		}
>  		new_shortname = 1;
>  	}
>  
> +	if (sched->map.command && strcmp(thread__comm_str(sched_in), sched->map.command))
> +		goto skip;
> +
> +	printf("  ");
> +
>  	for (i = 0; i < cpus_nr; i++) {
>  		struct perf_cpu cpu = {
>  			.cpu = sched->map.comp ? sched->map.comp_cpus[i].cpu : i,
> @@ -1678,6 +1686,7 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  out:
>  	color_fprintf(stdout, color, "\n");
>  
> +skip:
>  	thread__put(sched_in);
>  
>  	return 0;
> @@ -3560,6 +3569,8 @@ int cmd_sched(int argc, const char **argv)
>                      "highlight given CPUs in map"),
>  	OPT_STRING(0, "cpus", &sched.map.cpus_str, "cpus",
>                      "display given CPUs in map"),
> +	OPT_STRING(0, "command-name", &sched.map.command, "command",
> +		"map output only for the given command name"),
>  	OPT_PARENT(sched_options)
>  	};
>  	const struct option timehist_options[] = {
> -- 
> 2.39.1
>