From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>, Wei Li <liwei391@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Andi Kleen <ak@linux.intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Alexey Budankov <alexey.budankov@linux.intel.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andi Kleen <andi@firstfloor.org>,
Li Bin <huawei.libin@huawei.com>, Ingo Molnar <mingo@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] perf stat: Fix segfault when counting armv8_pmu events
Date: Fri, 2 Oct 2020 10:59:36 +0200 [thread overview]
Message-ID: <20201002085936.GE3999500@krava> (raw)
In-Reply-To: <20200924143623.GA357648@google.com>
On Thu, Sep 24, 2020 at 11:36:23PM +0900, Namhyung Kim wrote:
> On Wed, Sep 23, 2020 at 10:19:00PM +0200, Jiri Olsa wrote:
> > On Wed, Sep 23, 2020 at 11:15:06PM +0900, Namhyung Kim wrote:
> > > I think the problem is that armv8_pmu has a cpumask,
> > > and the user requested per-task events.
> > >
> > > The code tried to open the event with a dummy cpu map
> > > since it's not a cpu event, but the pmu has cpu map and
> > > it's passed to evsel. So there's confusion somewhere
> > > whether it should use evsel->cpus or a dummy map.
> >
> > you're right, I have following cpus file in pmu:
> >
> > # cat /sys/devices/armv8_pmuv3_0/cpus
> > 0-3
> >
> > covering all the cpus.. and once you have cpumask/cpus file,
> > you're system wide by default in current code, but we should
> > not crash ;-)
> >
> > I tried to cover this case in patch below and I probably broke
> > some other use cases, but perhaps we could allow to open counters
> > per cpus for given workload
> >
> > I'll try to look at this more tomorrow
>
> I'm thinking about a different approach, we can ignore cpu map
> for the ARM cpu PMU and use the dummy, not tested ;-)
>
> Thanks
> Namhyung
>
>
> diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
> index 2208444ecb44..cfcdbd7be066 100644
> --- a/tools/lib/perf/evlist.c
> +++ b/tools/lib/perf/evlist.c
> @@ -45,6 +45,9 @@ static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
> if (!evsel->own_cpus || evlist->has_user_cpus) {
> perf_cpu_map__put(evsel->cpus);
> evsel->cpus = perf_cpu_map__get(evlist->cpus);
> + } else if (!evsel->system_wide && perf_cpu_map__empty(evlist->cpus)) {
> + perf_cpu_map__put(evsel->cpus);
> + evsel->cpus = perf_cpu_map__get(evlist->cpus);
> } else if (evsel->cpus != evsel->own_cpus) {
> perf_cpu_map__put(evsel->cpus);
> evsel->cpus = perf_cpu_map__get(evsel->own_cpus);
>
Wei Li,
is this fixing your problem?
thanks,
jirka
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next prev parent reply other threads:[~2020-10-02 9:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 3:13 [PATCH 0/2] perf stat: Unbreak perf stat with ARMv8 PMU events Wei Li
2020-09-22 3:13 ` [PATCH 1/2] perf stat: Fix segfault when counting armv8_pmu events Wei Li
2020-09-22 19:23 ` Andi Kleen
2020-09-22 19:50 ` Andi Kleen
2020-09-24 14:14 ` liwei (GF)
2020-09-23 5:44 ` Jiri Olsa
2020-09-23 13:49 ` Namhyung Kim
2020-09-23 14:07 ` Jiri Olsa
2020-09-23 14:15 ` Namhyung Kim
2020-09-23 20:19 ` Jiri Olsa
2020-09-24 14:36 ` Namhyung Kim
2020-09-25 21:01 ` Jiri Olsa
2020-10-02 8:59 ` Jiri Olsa [this message]
2020-10-06 6:51 ` Song Bao Hua (Barry Song)
2020-09-22 3:13 ` [PATCH 2/2] perf stat: Unbreak perf stat with " Wei Li
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