diff options
| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-01-17 13:09:30 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-01-18 09:24:58 -0300 |
| commit | f350ee95498a3fa65c37ed597d9c051c6b2b6974 (patch) | |
| tree | f6afe1bff5c0fd4725b3967860f94db36aff9595 /tools/perf/util/evlist.c | |
| parent | 49de179577e7b05b57f625bf05cdc60a72de38d0 (diff) | |
perf evlist: No need to setup affinities when enabling events for pid targets
When the target is a pid, not started by 'perf stat' we need to enable
the events, and in that case there is no need to setup affinities as we
use a dummy CPU map, with just one entry set to -1.
So stop doing it to avoid this needless call to sched_getaffinity():
# strace -ke sched_getaffinity perf stat -e cycles -p 241957 sleep 1
<SNIP>
sched_getaffinity(0, 512, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31]) = 8
> /usr/lib64/libc-2.33.so(sched_getaffinity@@GLIBC_2.3.4+0x1a) [0xe6eea]
> /var/home/acme/bin/perf(affinity__setup+0x6a) [0x5329ca]
> /var/home/acme/bin/perf(__evlist__enable.constprop.0+0x23) [0x4b9693]
> /var/home/acme/bin/perf(enable_counters+0x14d) [0x42de5d]
> /var/home/acme/bin/perf(cmd_stat+0x2358) [0x4310c8]
> /var/home/acme/bin/perf(run_builtin+0x6a) [0x4a2cfa]
> /var/home/acme/bin/perf(main+0x612) [0x40f8c2]
> /usr/lib64/libc-2.33.so(__libc_start_main+0xd4) [0x27b74]
> /var/home/acme/bin/perf(_start+0x2d) [0x40fadd]
<SNIP>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220117160931.1191712-4-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/evlist.c')
| -rw-r--r-- | tools/perf/util/evlist.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 6e88d404b5b3..ae6d4363da76 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -487,12 +487,16 @@ static void __evlist__enable(struct evlist *evlist, char *evsel_name) { struct evsel *pos; struct evlist_cpu_iterator evlist_cpu_itr; - struct affinity affinity; + struct affinity saved_affinity, *affinity = NULL; - if (affinity__setup(&affinity) < 0) - return; + // See explanation in evlist__close() + if (!cpu_map__is_dummy(evlist->core.cpus)) { + if (affinity__setup(&saved_affinity) < 0) + return; + affinity = &saved_affinity; + } - evlist__for_each_cpu(evlist_cpu_itr, evlist, &affinity) { + evlist__for_each_cpu(evlist_cpu_itr, evlist, affinity) { pos = evlist_cpu_itr.evsel; if (evsel__strcmp(pos, evsel_name)) continue; @@ -500,7 +504,7 @@ static void __evlist__enable(struct evlist *evlist, char *evsel_name) continue; evsel__enable_cpu(pos, evlist_cpu_itr.cpu_map_idx); } - affinity__cleanup(&affinity); + affinity__cleanup(affinity); evlist__for_each_entry(evlist, pos) { if (evsel__strcmp(pos, evsel_name)) continue; |