From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752838AbcGSGyv (ORCPT ); Tue, 19 Jul 2016 02:54:51 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44394 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752269AbcGSGys (ORCPT ); Tue, 19 Jul 2016 02:54:48 -0400 Date: Mon, 18 Jul 2016 23:53:10 -0700 From: tip-bot for Mark Rutland Message-ID: Cc: kan.liang@intel.com, adrian.hunter@intel.com, wangnan0@huawei.com, hpa@zytor.com, mingo@kernel.org, mark.rutland@arm.com, peterz@infradead.org, hekuang@huawei.com, tglx@linutronix.de, jolsa@kernel.org, acme@redhat.com, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com Reply-To: hpa@zytor.com, wangnan0@huawei.com, kan.liang@intel.com, adrian.hunter@intel.com, hekuang@huawei.com, tglx@linutronix.de, peterz@infradead.org, alexander.shishkin@linux.intel.com, acme@redhat.com, linux-kernel@vger.kernel.org, jolsa@kernel.org, mingo@kernel.org, mark.rutland@arm.com In-Reply-To: <1468577293-19667-2-git-send-email-mark.rutland@arm.com> References: <1468577293-19667-2-git-send-email-mark.rutland@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf stat: Balance opening and reading events Git-Commit-ID: 00e727bb389359c81101b03d34fec8cc7be5168d 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: 00e727bb389359c81101b03d34fec8cc7be5168d Gitweb: http://git.kernel.org/tip/00e727bb389359c81101b03d34fec8cc7be5168d Author: Mark Rutland AuthorDate: Fri, 15 Jul 2016 11:08:10 +0100 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 18 Jul 2016 19:41:14 -0300 perf stat: Balance opening and reading events In create_perf_stat_counter, when a target CPU has not been provided, we call __perf_evsel__open with empty_cpu_map, and open a single FD per thread. However, in read_counter we assume that we opened events for the product of threads and CPUs described in the evsel's cpu_map. Thus, if an evsel has a cpu_map with more than one entry, we will attempt to access FDs that we didn't open. This could result in a number of problems (e.g. blocking while reading from STDIN if the fd memory happened to be initialised to zero). This is problematic for systems were a logical CPU PMU covers some arbitrary subset of CPUs. The cpu_map of any evsel for that PMU will be initialised based on the cpumask exposed through sysfs, even if the user requests per-thread events. Signed-off-by: Mark Rutland Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: He Kuang Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1468577293-19667-2-git-send-email-mark.rutland@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 8c5a3bf..0c16d20 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -290,8 +290,12 @@ perf_evsel__write_stat_event(struct perf_evsel *counter, u32 cpu, u32 thread, static int read_counter(struct perf_evsel *counter) { int nthreads = thread_map__nr(evsel_list->threads); - int ncpus = perf_evsel__nr_cpus(counter); - int cpu, thread; + int ncpus, cpu, thread; + + if (target__has_cpu(&target)) + ncpus = perf_evsel__nr_cpus(counter); + else + ncpus = 1; if (!counter->supported) return -ENOENT;