Re: [PATCH v4 03/35] perf cpumap: Add equal function

From: Ian Rogers
Date: Sat May 27 2023 - 02:05:47 EST

On Fri, May 26, 2023 at 6:40 PM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> 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@xxxxxxxxxx>
> > > Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > > ---
> > > 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@xxxxxxxxxx/

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