From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752978AbcGOKIu (ORCPT ); Fri, 15 Jul 2016 06:08:50 -0400 Received: from foss.arm.com ([217.140.101.70]:48149 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586AbcGOKIn (ORCPT ); Fri, 15 Jul 2016 06:08:43 -0400 From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: acme@kernel.org, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, hekuang@huawei.com, jolsa@kernel.org, kan.liang@intel.com, mark.rutland@arm.com, mingo@redhat.com, peterz@infradead.org, wangnan0@huawei.com Subject: [RFCv2 4/4] perf: util: support sysfs supported_cpumask file Date: Fri, 15 Jul 2016 11:08:13 +0100 Message-Id: <1468577293-19667-5-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1468577293-19667-1-git-send-email-mark.rutland@arm.com> References: <1468577293-19667-1-git-send-email-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For system PMUs, the perf tools have long expected a cpumask file under sysfs, describing the single CPU which they support events being opened/handled on. Prior patches in this series have reworked this support to support multiple CPUs in a mask, as is required to handle heterogeneous CPU PMUs. Unfortunately, adding a cpumask file to CPU PMUs would break existing userspace. Prior to this series, perf record will refuse to open events, and perf stat may unexpectedly block at exit time. In the absence of a cpumask, perf stat is functional. To address this, this patch adds support for a new file, supported_cpumask, which can be used to describe heterogeneous CPUs, without the risk of breaking existing userspace binaries. Signed-off-by: Mark Rutland --- tools/perf/util/pmu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index ddb0261..06c985c 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -445,14 +445,23 @@ static struct cpu_map *pmu_cpumask(const char *name) FILE *file; struct cpu_map *cpus; const char *sysfs = sysfs__mountpoint(); + const char *path_template[] = { + "%s/bus/event_source/devices/%s/cpumask", + "%s/bus/event_source/devices/%s/supported_cpumask", + NULL + }; + unsigned int i; if (!sysfs) return NULL; - snprintf(path, PATH_MAX, - "%s/bus/event_source/devices/%s/cpumask", sysfs, name); + for (i = 0; i < ARRAY_SIZE(path_template); i++) { + snprintf(path, PATH_MAX, *path_template, sysfs, name); + if (stat(path, &st) == 0) + break; + } - if (stat(path, &st) < 0) + if (!*path_template) return NULL; file = fopen(path, "r"); -- 1.9.1