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Message-ID: <CAP-5=fUEd9tRnnqzRogz5CUD8OZJMLE8kEcvROiYo4FEXzv8HQ@mail.gmail.com>
Date:   Fri, 26 May 2023 23:05:25 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        John Garry <john.g.garry@...cle.com>,
        Will Deacon <will@...nel.org>,
        James Clark <james.clark@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Jing Zhang <renyu.zj@...ux.alibaba.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Ming Wang <wangming01@...ngson.cn>,
        Huacai Chen <chenhuacai@...nel.org>,
        Sandipan Das <sandipan.das@....com>,
        Dmitrii Dolgov <9erthalion6@...il.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Ali Saidi <alisaidi@...zon.com>, Rob Herring <robh@...nel.org>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        Kang Minchul <tegongkang@...il.com>,
        linux-kernel@...r.kernel.org, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v4 03/35] perf cpumap: Add equal function

On Fri, May 26, 2023 at 6:40 PM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> Em Fri, May 26, 2023 at 10:32:12PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, May 26, 2023 at 02:53:38PM -0700, Ian Rogers escreveu:
> > > Equality is a useful property to compare after merging and
> > > intersecting maps.
> > >
> > > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > > Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
> > > ---
> > >  tools/lib/perf/cpumap.c              | 21 ++++++++++++++++
> > >  tools/lib/perf/include/perf/cpumap.h |  2 ++
> > >  tools/perf/tests/cpumap.c            | 37 ++++++++++++++++++++++++++++
> > >  3 files changed, 60 insertions(+)
> > >
> > > diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
> > > index d4f3a1a12522..48595a3ad69c 100644
> > > --- a/tools/lib/perf/cpumap.c
> > > +++ b/tools/lib/perf/cpumap.c
> > > @@ -321,6 +321,27 @@ bool perf_cpu_map__has(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
> > >     return perf_cpu_map__idx(cpus, cpu) != -1;
> > >  }
> > >
> > > +bool perf_cpu_map__equal(const struct perf_cpu_map *lhs, const struct perf_cpu_map *rhs)
> > > +{
> > > +   int nr;
> > > +
> > > +   if (lhs == rhs)
> > > +           return true;
> > > +
> > > +   if (!lhs || !rhs)
> > > +           return false;
> > > +
> > > +   nr = perf_cpu_map__nr(lhs);
> > > +   if (nr != perf_cpu_map__nr(rhs))
> > > +           return false;
> > > +
> > > +   for (int idx = 0; idx < nr; idx++) {
> > > +           if (RC_CHK_ACCESS(lhs)->map[idx].cpu != RC_CHK_ACCESS(rhs)->map[idx].cpu)
> > > +                   return false;
> >
> > Don't we have an accessor to avoid this RC_CHK_ACCESS()-> access?
>
>  In the following patch you use it:
>
> +bool perf_cpu_map__has_any_cpu(const struct perf_cpu_map *map)
> +{
> +       return map && perf_cpu_map__cpu(map, 0).cpu == -1;
> +}
>
> But it does extra checks you did already:
>
> struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
> {
>         struct perf_cpu result = {
>                 .cpu = -1
>         };
>
>         if (cpus && idx < RC_CHK_ACCESS(cpus)->nr)
>                 return RC_CHK_ACCESS(cpus)->map[idx];
>
>         return result;
> }
>
> Usually we have:
>
> struct perf_cpu __perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
> {
>         return RC_CHK_ACCESS(cpus)->map[idx];
> }
>
> struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
> {
>         struct perf_cpu result = {
>                 .cpu = -1
>         };
>
>         if (cpus && idx < __perf_cpu_map__nr(cpus))
>                 return __perf_cpu_map__cpu(cpus, idx);
>
>         return result;
> }
>
> Then you would have:
>
> bool perf_cpu_map__equal(const struct perf_cpu_map *lhs, const struct perf_cpu_map *rhs)
> {
>         int nr;
>
>         if (lhs == rhs)
>                 return true;
>
>         if (!lhs || !rhs)
>                 return false;
>
>         nr = __perf_cpu_map__nr(lhs);  // no need to check lhs again for NULL
>         if (nr != __perf_cpu_map__nr(rhs)) // ditto for rhs
>                 return false;
>
>         for (int idx = 0; idx < nr; idx++) {
>                 if (__perf_cpu_map__cpu(lhs, idx)->cpu != __perf_cpu_map__cpu(rhs, idx)->cpu)
>                         return false;
>

Thanks, I'll update for v5. Fwiw, on intersect, I keep forgetting to
mention that this was sent previously as:
https://lore.kernel.org/lkml/20220408035616.1356953-4-irogers@google.com/

Ian

> > > +   }
> > > +   return true;
> > > +}
> > > +
> > >  struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map)
> > >  {
> > >     struct perf_cpu result = {
> > > diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h
> > > index 0466c4216fbb..d0ae9552f8e2 100644
> > > --- a/tools/lib/perf/include/perf/cpumap.h
> > > +++ b/tools/lib/perf/include/perf/cpumap.h
> > > @@ -28,6 +28,8 @@ LIBPERF_API int perf_cpu_map__nr(const struct perf_cpu_map *cpus);
> > >  LIBPERF_API bool perf_cpu_map__empty(const struct perf_cpu_map *map);
> > >  LIBPERF_API struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map);
> > >  LIBPERF_API bool perf_cpu_map__has(const struct perf_cpu_map *map, struct perf_cpu cpu);
> > > +LIBPERF_API bool perf_cpu_map__equal(const struct perf_cpu_map *lhs,
> > > +                                const struct perf_cpu_map *rhs);
> > >
> > >  #define perf_cpu_map__for_each_cpu(cpu, idx, cpus)         \
> > >     for ((idx) = 0, (cpu) = perf_cpu_map__cpu(cpus, idx);   \
> > > diff --git a/tools/perf/tests/cpumap.c b/tools/perf/tests/cpumap.c
> > > index 83805690c209..7730fc2ab40b 100644
> > > --- a/tools/perf/tests/cpumap.c
> > > +++ b/tools/perf/tests/cpumap.c
> > > @@ -211,11 +211,48 @@ static int test__cpu_map_intersect(struct test_suite *test __maybe_unused,
> > >     return ret;
> > >  }
> > >
> > > +static int test__cpu_map_equal(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
> > > +{
> > > +   struct perf_cpu_map *any = perf_cpu_map__dummy_new();
> > > +   struct perf_cpu_map *one = perf_cpu_map__new("1");
> > > +   struct perf_cpu_map *two = perf_cpu_map__new("2");
> > > +   struct perf_cpu_map *empty = perf_cpu_map__intersect(one, two);
> > > +   struct perf_cpu_map *pair = perf_cpu_map__new("1-2");
> > > +   struct perf_cpu_map *tmp;
> > > +   struct perf_cpu_map *maps[] = {empty, any, one, two, pair};
> > > +
> > > +   for (size_t i = 0; i < ARRAY_SIZE(maps); i++) {
> > > +           /* Maps equal themself. */
> > > +           TEST_ASSERT_VAL("equal", perf_cpu_map__equal(maps[i], maps[i]));
> > > +           for (size_t j = 0; j < ARRAY_SIZE(maps); j++) {
> > > +                   /* Maps dont't equal each other. */
> > > +                   if (i == j)
> > > +                           continue;
> > > +                   TEST_ASSERT_VAL("not equal", !perf_cpu_map__equal(maps[i], maps[j]));
> > > +           }
> > > +   }
> > > +
> > > +   /* Maps equal made maps. */
> > > +   tmp = perf_cpu_map__merge(perf_cpu_map__get(one), two);
> > > +   TEST_ASSERT_VAL("pair", perf_cpu_map__equal(pair, tmp));
> > > +   perf_cpu_map__put(tmp);
> > > +
> > > +   tmp = perf_cpu_map__intersect(pair, one);
> > > +   TEST_ASSERT_VAL("one", perf_cpu_map__equal(one, tmp));
> > > +   perf_cpu_map__put(tmp);
> > > +
> > > +   for (size_t i = 0; i < ARRAY_SIZE(maps); i++)
> > > +           perf_cpu_map__put(maps[i]);
> > > +
> > > +   return TEST_OK;
> > > +}
> > > +
> > >  static struct test_case tests__cpu_map[] = {
> > >     TEST_CASE("Synthesize cpu map", cpu_map_synthesize),
> > >     TEST_CASE("Print cpu map", cpu_map_print),
> > >     TEST_CASE("Merge cpu map", cpu_map_merge),
> > >     TEST_CASE("Intersect cpu map", cpu_map_intersect),
> > > +   TEST_CASE("Equal cpu map", cpu_map_equal),
> > >     {       .name = NULL, }
> > >  };
> > >
> > > --
> > > 2.41.0.rc0.172.g3f132b7071-goog
> > >
> >
> > --
> >
> > - Arnaldo
>
> --
>
> - Arnaldo

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