From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752588AbdHXIV5 (ORCPT ); Thu, 24 Aug 2017 04:21:57 -0400 Received: from terminus.zytor.com ([65.50.211.136]:43705 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752229AbdHXIVy (ORCPT ); Thu, 24 Aug 2017 04:21:54 -0400 Date: Thu, 24 Aug 2017 01:20:44 -0700 From: tip-bot for Andi Kleen Message-ID: Cc: jolsa@kernel.org, acme@redhat.com, ak@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de Reply-To: linux-kernel@vger.kernel.org, hpa@zytor.com, acme@redhat.com, ak@linux.intel.com, jolsa@kernel.org, tglx@linutronix.de, mingo@kernel.org In-Reply-To: <20170811232634.30465-7-andi@firstfloor.org> References: <20170811232634.30465-7-andi@firstfloor.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf tools: Add utility function to detect SMT status Git-Commit-ID: de5077c4e38f2a51f50d28bdd5e4a0f14b3d16ff X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: de5077c4e38f2a51f50d28bdd5e4a0f14b3d16ff Gitweb: http://git.kernel.org/tip/de5077c4e38f2a51f50d28bdd5e4a0f14b3d16ff Author: Andi Kleen AuthorDate: Fri, 11 Aug 2017 16:26:22 -0700 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 22 Aug 2017 12:09:04 -0300 perf tools: Add utility function to detect SMT status Add an smt_on() function to return if SMT is enabled or disabled. Used in the next patch. Signed-off-by: Andi Kleen Acked-by: Jiri Olsa Link: http://lkml.kernel.org/r/20170811232634.30465-7-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/Build | 1 + tools/perf/util/smt.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/smt.h | 6 ++++++ 3 files changed, 51 insertions(+) diff --git a/tools/perf/util/Build b/tools/perf/util/Build index 8d49a98..94518c1 100644 --- a/tools/perf/util/Build +++ b/tools/perf/util/Build @@ -22,6 +22,7 @@ libperf-y += rbtree.o libperf-y += libstring.o libperf-y += bitmap.o libperf-y += hweight.o +libperf-y += smt.o libperf-y += quote.o libperf-y += strbuf.o libperf-y += string.o diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c new file mode 100644 index 0000000..453f6f6 --- /dev/null +++ b/tools/perf/util/smt.c @@ -0,0 +1,44 @@ +#include +#include +#include +#include +#include "api/fs/fs.h" +#include "smt.h" + +int smt_on(void) +{ + static bool cached; + static int cached_result; + int cpu; + int ncpu; + + if (cached) + return cached_result; + + ncpu = sysconf(_SC_NPROCESSORS_CONF); + for (cpu = 0; cpu < ncpu; cpu++) { + unsigned long long siblings; + char *str; + size_t strlen; + char fn[256]; + + snprintf(fn, sizeof fn, + "devices/system/cpu/cpu%d/topology/thread_siblings", + cpu); + if (sysfs__read_str(fn, &str, &strlen) < 0) + continue; + /* Entry is hex, but does not have 0x, so need custom parser */ + siblings = strtoull(str, NULL, 16); + free(str); + if (hweight64(siblings) > 1) { + cached_result = 1; + cached = true; + break; + } + } + if (!cached) { + cached_result = 0; + cached = true; + } + return cached_result; +} diff --git a/tools/perf/util/smt.h b/tools/perf/util/smt.h new file mode 100644 index 0000000..b8414b7 --- /dev/null +++ b/tools/perf/util/smt.h @@ -0,0 +1,6 @@ +#ifndef SMT_H +#define SMT_H 1 + +int smt_on(void); + +#endif