The following commit has been merged into the perf/core branch of tip: Commit-ID: bb629484d924118e3b1d8652177040115adcba01 Gitweb: https://git.kernel.org/tip/bb629484d924118e3b1d8652177040115adcba01 Author: Konstantin Khlebnikov <khlebni...@yandex-team.ru> AuthorDate: Wed, 29 Apr 2020 19:23:41 +03:00 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitterDate: Tue, 05 May 2020 16:35:29 -03:00
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 <khlebni...@yandex-team.ru> Cc: Andi Kleen <a...@linux.intel.com> Cc: Dmitry Monakhov <dmtrmonak...@yandex-team.ru> Cc: Jiri Olsa <jo...@kernel.org> Cc: Kan Liang <kan.li...@linux.intel.com> Cc: Peter Zijlstra <pet...@infradead.org> Link: http://lore.kernel.org/lkml/158817741394.748034.9273604089138009552.stgit@buzz Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/smt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 8481842..20bacd5 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;
