[PATCH] perf: sched map skips redundant lines with cpu filters

[PATCH] perf: sched map skips redundant lines with cpu filters

[Fernand Sieber]

perf sched map supports cpu filter.
However, even with cpu filters active, any context switch currently
corresponds to a separate line.
As result, context switches on irrelevant cpus result to redundant lines,
which makes the output particlularly difficult to read on wide
architectures.

Fix it by skipping printing for irrelevant CPUs.

Example snippet of output before fix:

  *B0       1.461147 secs
   B0
   B0
   B0
  *G0       1.517139 secs

After fix:

  *B0       1.461147 secs
  *G0       1.517139 secs

Signed-off-by: Fernand Sieber <sieberf@amazon.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 tools/perf/builtin-sched.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 7422c930abaf..aa59f763ca46 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1594,8 +1594,6 @@ 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")) {
@@ -1622,6 +1620,11 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
 		new_shortname = 1;
 	}
 
+	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
+		goto out;
+
+	printf("  ");
+
 	for (i = 0; i < cpus_nr; i++) {
 		struct perf_cpu cpu = {
 			.cpu = sched->map.comp ? sched->map.comp_cpus[i].cpu : i,
@@ -1656,9 +1659,6 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
 			color_fprintf(stdout, color, "   ");
 	}
 
-	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
-		goto out;
-
 	timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
 	color_fprintf(stdout, color, "  %12s secs ", stimestamp);
 	if (new_shortname || tr->comm_changed || (verbose > 0 && thread__tid(sched_in))) {
@@ -1675,9 +1675,9 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
 	if (sched->map.comp && new_cpu)
 		color_fprintf(stdout, color, " (CPU %d)", this_cpu);
 
-out:
 	color_fprintf(stdout, color, "\n");
 
+out:
 	thread__put(sched_in);
 
 	return 0;
-- 
2.40.1

Re: [PATCH] perf: sched map skips redundant lines with cpu filters

[Namhyung Kim]

Hello,

On Fri, Jun 14, 2024 at 12:49 AM Fernand Sieber <sieberf@amazon.com> wrote:
>
> perf sched map supports cpu filter.
> However, even with cpu filters active, any context switch currently
> corresponds to a separate line.
> As result, context switches on irrelevant cpus result to redundant lines,
> which makes the output particlularly difficult to read on wide
> architectures.
>
> Fix it by skipping printing for irrelevant CPUs.
>
> Example snippet of output before fix:
>
>   *B0       1.461147 secs
>    B0
>    B0
>    B0
>   *G0       1.517139 secs
>
> After fix:
>
>   *B0       1.461147 secs
>   *G0       1.517139 secs
>
> Signed-off-by: Fernand Sieber <sieberf@amazon.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> ---
>  tools/perf/builtin-sched.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 7422c930abaf..aa59f763ca46 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -1594,8 +1594,6 @@ 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")) {
> @@ -1622,6 +1620,11 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>                 new_shortname = 1;
>         }
>
> +       if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> +               goto out;
> +
> +       printf("  ");
> +
>         for (i = 0; i < cpus_nr; i++) {
>                 struct perf_cpu cpu = {
>                         .cpu = sched->map.comp ? sched->map.comp_cpus[i].cpu : i,
> @@ -1656,9 +1659,6 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>                         color_fprintf(stdout, color, "   ");
>         }
>
> -       if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> -               goto out;
> -
>         timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
>         color_fprintf(stdout, color, "  %12s secs ", stimestamp);
>         if (new_shortname || tr->comm_changed || (verbose > 0 && thread__tid(sched_in))) {
> @@ -1675,9 +1675,9 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>         if (sched->map.comp && new_cpu)
>                 color_fprintf(stdout, color, " (CPU %d)", this_cpu);
>
> -out:
>         color_fprintf(stdout, color, "\n");
>
> +out:
>         thread__put(sched_in);
>
>         return 0;
> --
> 2.40.1
>
>

Re: [PATCH] perf: sched map skips redundant lines with cpu filters

[Madadi Vineeth Reddy]

Hi Fernand,

On 14/06/24 13:05, Fernand Sieber wrote:
> perf sched map supports cpu filter.
> However, even with cpu filters active, any context switch currently
> corresponds to a separate line.
> As result, context switches on irrelevant cpus result to redundant lines,
> which makes the output particlularly difficult to read on wide
> architectures.
> 
> Fix it by skipping printing for irrelevant CPUs.
> 
> Example snippet of output before fix:
> 
>   *B0       1.461147 secs
>    B0
>    B0
>    B0
>   *G0       1.517139 secs
> 
> After fix:
> 
>   *B0       1.461147 secs
>   *G0       1.517139 secs

Yes, this makes sense. The current implementation doesn't even print timestamp
for the redundant lines as shown in the example below.

   .  *F0   708529.114889 secs F0 => schbench:278841
   .   F0 
   .   F0 
   .  *.    708529.114919 secs 

It makes sense to remove them entirely since we can still infer the sched-out
time for the selected CPUs implicitly.

Reviewed-and-tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>

Thanks and Regards
Madadi Vineeth Reddy
> 
> Signed-off-by: Fernand Sieber <sieberf@amazon.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> ---
>  tools/perf/builtin-sched.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 7422c930abaf..aa59f763ca46 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -1594,8 +1594,6 @@ 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")) {
> @@ -1622,6 +1620,11 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  		new_shortname = 1;
>  	}
>  
> +	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> +		goto out;
> +
> +	printf("  ");
> +
>  	for (i = 0; i < cpus_nr; i++) {
>  		struct perf_cpu cpu = {
>  			.cpu = sched->map.comp ? sched->map.comp_cpus[i].cpu : i,
> @@ -1656,9 +1659,6 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  			color_fprintf(stdout, color, "   ");
>  	}
>  
> -	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> -		goto out;
> -
>  	timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
>  	color_fprintf(stdout, color, "  %12s secs ", stimestamp);
>  	if (new_shortname || tr->comm_changed || (verbose > 0 && thread__tid(sched_in))) {
> @@ -1675,9 +1675,9 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  	if (sched->map.comp && new_cpu)
>  		color_fprintf(stdout, color, " (CPU %d)", this_cpu);
>  
> -out:
>  	color_fprintf(stdout, color, "\n");
>  
> +out:
>  	thread__put(sched_in);
>  
>  	return 0;

Re: [PATCH] perf: sched map skips redundant lines with cpu filters

[Madadi Vineeth Reddy]

Hi Fernand,

On 14/06/24 13:05, Fernand Sieber wrote:
> perf sched map supports cpu filter.
> However, even with cpu filters active, any context switch currently
> corresponds to a separate line.
> As result, context switches on irrelevant cpus result to redundant lines,
> which makes the output particlularly difficult to read on wide
> architectures.
> 
> Fix it by skipping printing for irrelevant CPUs.
> 
> Example snippet of output before fix:
> 
>   *B0       1.461147 secs
>    B0
>    B0
>    B0
>   *G0       1.517139 secs
> 
> After fix:
> 
>   *B0       1.461147 secs
>   *G0       1.517139 secs

Yes, this makes sense. The current implementation doesn't even print timestamp
for the redundant lines as shown in the example below.

   .  *F0   708529.114889 secs F0 => schbench:278841
   .   F0 
   .   F0 
   .  *.    708529.114919 secs 

It makes sense to remove them entirely since we can still infer the sched-out
time for the selected CPUs implicitly.

Reviewed-and-tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>

Thanks and Regards
Madadi Vineeth Reddy

> 
> Signed-off-by: Fernand Sieber <sieberf@amazon.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> ---
>  tools/perf/builtin-sched.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 7422c930abaf..aa59f763ca46 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -1594,8 +1594,6 @@ 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")) {
> @@ -1622,6 +1620,11 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  		new_shortname = 1;
>  	}
>  
> +	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> +		goto out;
> +
> +	printf("  ");
> +
>  	for (i = 0; i < cpus_nr; i++) {
>  		struct perf_cpu cpu = {
>  			.cpu = sched->map.comp ? sched->map.comp_cpus[i].cpu : i,
> @@ -1656,9 +1659,6 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  			color_fprintf(stdout, color, "   ");
>  	}
>  
> -	if (sched->map.cpus && !perf_cpu_map__has(sched->map.cpus, this_cpu))
> -		goto out;
> -
>  	timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
>  	color_fprintf(stdout, color, "  %12s secs ", stimestamp);
>  	if (new_shortname || tr->comm_changed || (verbose > 0 && thread__tid(sched_in))) {
> @@ -1675,9 +1675,9 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
>  	if (sched->map.comp && new_cpu)
>  		color_fprintf(stdout, color, " (CPU %d)", this_cpu);
>  
> -out:
>  	color_fprintf(stdout, color, "\n");
>  
> +out:
>  	thread__put(sched_in);
>  
>  	return 0;

Re: [PATCH] perf: sched map skips redundant lines with cpu filters

[Namhyung Kim]

On Fri, 14 Jun 2024 09:35:17 +0200, Fernand Sieber wrote:

> perf sched map supports cpu filter.
> However, even with cpu filters active, any context switch currently
> corresponds to a separate line.
> As result, context switches on irrelevant cpus result to redundant lines,
> which makes the output particlularly difficult to read on wide
> architectures.
> 
> [...]

Applied to perf-tools-next, thanks!

Best regards,
Namhyung