From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752531AbcGROaa (ORCPT ); Mon, 18 Jul 2016 10:30:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42128 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752220AbcGROaZ (ORCPT ); Mon, 18 Jul 2016 10:30:25 -0400 Date: Mon, 18 Jul 2016 16:30:18 +0200 From: Jiri Olsa To: Mark Rutland Cc: linux-kernel@vger.kernel.org, acme@kernel.org, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, hekuang@huawei.com, jolsa@kernel.org, kan.liang@intel.com, mingo@redhat.com, peterz@infradead.org, wangnan0@huawei.com Subject: Re: [RFCv2 4/4] perf: util: support sysfs supported_cpumask file Message-ID: <20160718143018.GA4813@krava> References: <1468577293-19667-1-git-send-email-mark.rutland@arm.com> <1468577293-19667-5-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1468577293-19667-5-git-send-email-mark.rutland@arm.com> User-Agent: Mutt/1.6.2 (2016-07-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 18 Jul 2016 14:30:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 15, 2016 at 11:08:13AM +0100, Mark Rutland wrote: > For system PMUs, the perf tools have long expected a cpumask file under > sysfs, describing the single CPU which they support events being single cpu? it's cpumask.. > 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, I'm lost.. we already have 'cpumask' file under pmu.. > 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. is there kernel patch adding supported_cpumask support? thanks, jirka > > 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 >