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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2020-04-29 19:23:41 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-05-05 16:35:29 -0300 |
| commit | bb629484d924118e3b1d8652177040115adcba01 (patch) | |
| tree | 63c5b651859bbc6ad189d029efa52f020a65ed20 | |
| parent | 846de4371fdfddfa49481e3d04884539870dc127 (diff) | |
| download | linux-stable-bb629484d924118e3b1d8652177040115adcba01.tar.gz linux-stable-bb629484d924118e3b1d8652177040115adcba01.tar.bz2 linux-stable-bb629484d924118e3b1d8652177040115adcba01.zip | |
perf tools: Simplify checking if SMT is active.
SMT now could be disabled via "/sys/devices/system/cpu/smt/control".
Status is shown in "/sys/devices/system/cpu/smt/active" simply as "0" / "1".
If this knob isn't here then fallback to checking topology as before.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/158817741394.748034.9273604089138009552.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/smt.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 8481842e9edb..20bacd5972ad 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -15,6 +15,9 @@ int smt_on(void) if (cached) return cached_result; + if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0) + goto done; + ncpu = sysconf(_SC_NPROCESSORS_CONF); for (cpu = 0; cpu < ncpu; cpu++) { unsigned long long siblings; @@ -42,6 +45,7 @@ int smt_on(void) } if (!cached) { cached_result = 0; +done: cached = true; } return cached_result; |