Messages in this thread | | | Date | Tue, 3 May 2022 07:51:50 +0300 | Subject | Re: [PATCH v4 4/6] perf cpumap: Handle dummy maps as empty in subset | From | Adrian Hunter <> |
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On 2/05/22 20:04, Ian Rogers wrote: > On Mon, May 2, 2022 at 9:13 AM Adrian Hunter <adrian.hunter@intel.com> wrote: >> >> On 30/04/22 09:23, Ian Rogers wrote: >>> perf_cpu_map__empty is true for empty and dummy maps. Make is_subset >>> respect that. >> >> I think this might be the opposite of what I am trying to do, which is >> enable all_cpus to represent all the "cpu" values (3rd parameter of >> perf_event_open()) to iterate over including -1 so that per-thread and >> per-cpu events can be mixed. > > Wouldn't you iterate over the cpus of the evsel?
When mmapping perf events, it is necessary to iterate all (user_requested) cpus / threads in order to conveniently set-output events on the same cpu / thread.
> I'm not sure using > all_cpus in that way makes sense
It does if you want to mix per-cpu and per-thread (cpu == -1) events. As I wrote previously, the cpus is then seen as a list of values for parameter 3 of perf_event_open(), and therefore includes -1.
> it also violates the definition of > empty.
That can be renamed, since it is typically being used to mean per-thread (i.e. per-task context)
> > Thanks, > Ian > >>> >>> Signed-off-by: Ian Rogers <irogers@google.com> >>> --- >>> tools/lib/perf/cpumap.c | 4 ++-- >>> tools/perf/tests/cpumap.c | 10 +++++++++- >>> 2 files changed, 11 insertions(+), 3 deletions(-) >>> >>> diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c >>> index 384d5e076ee4..9c83675788c2 100644 >>> --- a/tools/lib/perf/cpumap.c >>> +++ b/tools/lib/perf/cpumap.c >>> @@ -322,9 +322,9 @@ struct perf_cpu perf_cpu_map__max(struct perf_cpu_map *map) >>> /** Is 'b' a subset of 'a'. */ >>> bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu_map *b) >>> { >>> - if (a == b || !b) >>> + if (a == b || perf_cpu_map__empty(b)) >>> return true; >>> - if (!a || b->nr > a->nr) >>> + if (perf_cpu_map__empty(a) || b->nr > a->nr) >>> return false; >>> >>> for (int i = 0, j = 0; i < a->nr; i++) { >>> diff --git a/tools/perf/tests/cpumap.c b/tools/perf/tests/cpumap.c >>> index f94929ebb54b..d52b58395385 100644 >>> --- a/tools/perf/tests/cpumap.c >>> +++ b/tools/perf/tests/cpumap.c >>> @@ -128,13 +128,21 @@ static int test__cpu_map_merge(struct test_suite *test __maybe_unused, int subte >>> struct perf_cpu_map *a = perf_cpu_map__new("4,2,1"); >>> struct perf_cpu_map *b = perf_cpu_map__new("4,5,7"); >>> struct perf_cpu_map *c = perf_cpu_map__merge(a, b); >>> + struct perf_cpu_map *d = perf_cpu_map__dummy_new(); >>> + struct perf_cpu_map *e = perf_cpu_map__merge(b, d); >>> char buf[100]; >>> >>> TEST_ASSERT_VAL("failed to merge map: bad nr", perf_cpu_map__nr(c) == 5); >>> cpu_map__snprint(c, buf, sizeof(buf)); >>> TEST_ASSERT_VAL("failed to merge map: bad result", !strcmp(buf, "1-2,4-5,7")); >>> - perf_cpu_map__put(b); >>> + >>> + TEST_ASSERT_VAL("failed to merge map: bad nr", perf_cpu_map__nr(e) == 3); >>> + cpu_map__snprint(e, buf, sizeof(buf)); >>> + TEST_ASSERT_VAL("failed to merge map: bad result", !strcmp(buf, "4-5,7")); >>> + >>> perf_cpu_map__put(c); >>> + perf_cpu_map__put(d); >>> + perf_cpu_map__put(e); >>> return 0; >>> } >>> >>
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