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

Arnaldo Carvalho de Melo
2023-05-27T01:40:24Z

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@google.com>
> > Reviewed-by: Kan Liang <kan.liang@linux.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;

> > + }
> > + 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