[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAP-5=fU6yqFKS+dYZ9VcoPftEGh3+oebLsZSOgEaG-XdNFZ7pQ@mail.gmail.com>
Date: Thu, 6 Oct 2022 11:43:49 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...nel.org>, Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-perf-users@...r.kernel.org,
Kan Liang <kan.liang@...ux.intel.com>,
Leo Yan <leo.yan@...aro.org>
Subject: Re: [PATCH 1/5] libperf: Populate system-wide evsel maps
On Mon, Oct 3, 2022 at 1:46 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> Setting proper cpu and thread maps for system wide evsels regardless of
> user requested cpu in __perf_evlist__propagate_maps(). Those evsels
> need to be active on all cpus always. Do it in the libperf so that we
> can guarantee it has proper maps.
>
> Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> tools/lib/perf/evlist.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
> index 6b1bafe267a4..187129652ab6 100644
> --- a/tools/lib/perf/evlist.c
> +++ b/tools/lib/perf/evlist.c
> @@ -40,11 +40,11 @@ static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
> * We already have cpus for evsel (via PMU sysfs) so
> * keep it, if there's no target cpu list defined.
> */
This comment is for the 'else if' case and so is a little out of place
before the system wide test.
> - if (!evsel->own_cpus ||
> - (!evsel->system_wide && evlist->has_user_cpus) ||
> - (!evsel->system_wide &&
> - !evsel->requires_cpu &&
> - perf_cpu_map__empty(evlist->user_requested_cpus))) {
> + if (evsel->system_wide) {
> + perf_cpu_map__put(evsel->cpus);
> + evsel->cpus = perf_cpu_map__new(NULL);
Looking at perf_cpu_map__new, will this mean that in system wide mode
every event/evsel will now read /sys/devices/system/cpu/online here?
We may want to cache the cpumap to avoid this.
Thanks,
Ian
> + } else if (!evsel->own_cpus || evlist->has_user_cpus ||
> + (!evsel->requires_cpu && perf_cpu_map__empty(evlist->user_requested_cpus))) {
> perf_cpu_map__put(evsel->cpus);
> evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
> } else if (evsel->cpus != evsel->own_cpus) {
> @@ -52,7 +52,10 @@ static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
> evsel->cpus = perf_cpu_map__get(evsel->own_cpus);
> }
>
> - if (!evsel->system_wide) {
> + if (evsel->system_wide) {
> + perf_thread_map__put(evsel->threads);
> + evsel->threads = perf_thread_map__new_dummy();
> + } else {
> perf_thread_map__put(evsel->threads);
> evsel->threads = perf_thread_map__get(evlist->threads);
> }
> --
> 2.38.0.rc1.362.ged0d419d3c-goog
>
Powered by blists - more mailing lists