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Date:   Wed, 30 Oct 2019 11:06:06 +0100
From:   Jiri Olsa <jolsa@redhat.com>
To:     Andi Kleen <andi@firstfloor.org>
Cc:     acme@kernel.org, jolsa@kernel.org, eranian@google.com,
        linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v3 3/7] perf evsel: Add iterator to iterate over events
 ordered by CPU
Message-ID: <20191030100606.GG20826@krava>
References: <20191025181417.10670-1-andi@firstfloor.org>
 <20191025181417.10670-4-andi@firstfloor.org>
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On Fri, Oct 25, 2019 at 11:14:13AM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>=20
> Add some common code that is needed to iterate over all events
> in CPU order. Used in followon patches
>=20
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
>=20
> ---
>=20
> v2: Add cpumap__for_each_cpu macro to factor out some common code
> ---
>  tools/perf/util/cpumap.h |  8 ++++++++
>  tools/perf/util/evlist.c | 33 +++++++++++++++++++++++++++++++++
>  tools/perf/util/evlist.h |  4 ++++
>  tools/perf/util/evsel.h  |  1 +
>  4 files changed, 46 insertions(+)
>=20
> diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
> index 2553bef1279d..a9b13d72fd29 100644
> --- a/tools/perf/util/cpumap.h
> +++ b/tools/perf/util/cpumap.h
> @@ -60,4 +60,12 @@ int cpu_map__build_map(struct perf_cpu_map *cpus, stru=
ct perf_cpu_map **res,
> =20
>  int cpu_map__cpu(struct perf_cpu_map *cpus, int idx);
>  bool cpu_map__has(struct perf_cpu_map *cpus, int cpu);
> +
> +#define __cpumap__for_each_cpu(cpus, index, cpu, maxcpu)\
> +=09for ((index) =3D 0; =09=09=09=09\
> +=09     (cpu) =3D (index) < (maxcpu) ? (cpus)->map[index] : -1, (index) =
< (maxcpu); \
> +=09     (index)++)
> +#define cpumap__for_each_cpu(cpus, index, cpu) \
> +=09__cpumap__for_each_cpu(cpus, index, cpu, (cpus)->nr)
> +
>  #endif /* __PERF_CPUMAP_H */
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index fdce590d2278..da3c8f8ef68e 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -342,6 +342,39 @@ static int perf_evlist__nr_threads(struct evlist *ev=
list,
>  =09=09return perf_thread_map__nr(evlist->core.threads);
>  }
> =20
> +struct perf_cpu_map *evlist__cpu_iter_start(struct evlist *evlist)
> +{
> +=09struct perf_cpu_map *cpus;
> +=09struct evsel *pos;
> +
> +=09/*
> +=09 * evlist->cpus is not necessarily a superset of all the
> +=09 * event's cpus, so compute our own super set. This
> +=09 * assume that there is a super set
> +=09 */
> +=09cpus =3D evlist->core.cpus;
> +=09evlist__for_each_entry(evlist, pos) {
> +=09=09pos->cpu_index =3D 0;
> +=09=09if (pos->core.cpus->nr > cpus->nr)
> +=09=09=09cpus =3D pos->core.cpus;
> +=09}
> +=09return cpus;

I might not understand the reason for cpu_index, but=20
imagine something like below should be enough, no?

=09make evlist->all_cpus that contains all events cpus + evlist->core.cpus,
        and iterate it via:

=09evlist__for_each_cpu(evlist, cpu) {
=09=09affinity__set(&affinity, cpu);

=09=09evlist__for_each_entry(evlist, evsel) {
=09=09=09if (!cpu_map__has(perf_evsel__cpus(&evsel->core), cpu)
=09=09=09=09continue;

=09=09=09// here we have evsel with its cpu running on given cpu
=09=09}
=09}

jirka