From: Ian Rogers <irogers@google.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH v2 2/5] perf record: Prevent override of attr->sample_period for libpfm4 events
Date: Fri, 4 Sep 2020 09:22:10 -0700 [thread overview]
Message-ID: <CAP-5=fWOSi4B3g1DARkh6Di-gU4FgmjnhbPYRBdvSdLSy_KC5Q@mail.gmail.com> (raw)
In-Reply-To: <20200904160303.GD939481@krava>
On Fri, Sep 4, 2020 at 9:03 AM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Thu, Sep 03, 2020 at 10:41:14PM -0700, Ian Rogers wrote:
> > On Wed, Jul 29, 2020 at 4:24 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > On Tue, Jul 28, 2020 at 9:10 AM Jiri Olsa <jolsa@redhat.com> wrote:
> > > >
> > > > On Tue, Jul 28, 2020 at 05:59:46PM +0200, Jiri Olsa wrote:
> > > > > On Tue, Jul 28, 2020 at 01:57:31AM -0700, Ian Rogers wrote:
> > > > > > From: Stephane Eranian <eranian@google.com>
> > > > > >
> > > > > > Before:
> > > > > > $ perf record -c 10000 --pfm-events=cycles:period=77777
> > > > > >
> > > > > > Would yield a cycles event with period=10000, instead of 77777.
> > > > > >
> > > > > > This was due to an ordering issue between libpfm4 parsing
> > > > > > the event string and perf record initializing the event.
> > > > > >
> > > > > > This patch fixes the problem by preventing override for
> > > > > > events with attr->sample_period != 0 by the time
> > > > > > perf_evsel__config() is invoked. This seems to have been the
> > > > > > intent of the author.
> > > > > >
> > > > > > Signed-off-by: Stephane Eranian <eranian@google.com>
> > > > > > Reviewed-by: Ian Rogers <irogers@google.com>
> > > > > > ---
> > > > > > tools/perf/util/evsel.c | 3 +--
> > > > > > 1 file changed, 1 insertion(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > > > > > index 811f538f7d77..8afc24e2ec52 100644
> > > > > > --- a/tools/perf/util/evsel.c
> > > > > > +++ b/tools/perf/util/evsel.c
> > > > > > @@ -976,8 +976,7 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
> > > > > > * We default some events to have a default interval. But keep
> > > > > > * it a weak assumption overridable by the user.
> > > > > > */
> > > > > > - if (!attr->sample_period || (opts->user_freq != UINT_MAX ||
> > > > > > - opts->user_interval != ULLONG_MAX)) {
> > > > > > + if (!attr->sample_period) {
> > > > >
> > > > > I was wondering why this wouldn't break record/top
> > > > > but we take care of the via record_opts__config
> > > > >
> > > > > as long as 'perf test attr' works it looks ok to me
> > > >
> > > > hum ;-)
> > > >
> > > > [jolsa@krava perf]$ sudo ./perf test 17 -v
> > > > 17: Setup struct perf_event_attr :
> > > > ...
> > > > running './tests/attr/test-record-C0'
> > > > expected sample_period=4000, got 3000
> > > > FAILED './tests/attr/test-record-C0' - match failure
> > >
> > > I'm not able to reproduce this. Do you have a build configuration or
> > > something else to look at? The test doesn't seem obviously connected
> > > with this patch.
> > >
> > > Thanks,
> > > Ian
> >
> > Jiri, any update? Thanks,
>
> sorry, I rebased and ran it again and it passes for me now,
> so it got fixed along the way
No worries, thanks for the update! It'd be nice to land this and the
other libpfm fixes.
Ian
> jirka
>
next prev parent reply other threads:[~2020-09-04 16:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 8:57 [PATCH v2 0/5] Fixes for setting event freq/periods Ian Rogers
2020-07-28 8:57 ` [PATCH v2 1/5] perf record: Set PERF_RECORD_PERIOD if attr->freq is set Ian Rogers
2020-07-28 15:43 ` Jiri Olsa
2020-07-28 16:03 ` Arnaldo Carvalho de Melo
2020-07-29 15:11 ` Athira Rajeev
2020-07-29 18:52 ` Arnaldo Carvalho de Melo
2020-07-29 21:43 ` Ian Rogers
2020-09-04 5:39 ` Ian Rogers
2020-07-28 8:57 ` [PATCH v2 2/5] perf record: Prevent override of attr->sample_period for libpfm4 events Ian Rogers
2020-07-28 15:59 ` Jiri Olsa
2020-07-28 16:09 ` Jiri Olsa
2020-07-29 23:24 ` Ian Rogers
2020-09-04 5:41 ` Ian Rogers
2020-09-04 16:03 ` Jiri Olsa
2020-09-04 16:22 ` Ian Rogers [this message]
2020-09-04 18:48 ` Arnaldo Carvalho de Melo
2020-09-04 18:50 ` Arnaldo Carvalho de Melo
2020-09-04 18:51 ` Arnaldo Carvalho de Melo
2020-09-11 22:34 ` Ian Rogers
2020-09-12 3:02 ` Ian Rogers
2020-07-29 18:54 ` Arnaldo Carvalho de Melo
2020-07-28 8:57 ` [PATCH v2 3/5] perf test: Ensure sample_period is set " Ian Rogers
2020-07-28 12:45 ` Arnaldo Carvalho de Melo
2020-07-28 8:57 ` [PATCH v2 4/5] perf record: Don't clear event's period if set by a term Ian Rogers
2020-07-29 18:58 ` Arnaldo Carvalho de Melo
2020-08-04 10:08 ` Adrian Hunter
2020-08-04 13:33 ` Ian Rogers
2020-08-04 14:48 ` Adrian Hunter
2020-08-04 15:50 ` Ian Rogers
2020-09-04 5:43 ` Ian Rogers
2020-09-07 6:36 ` Adrian Hunter
2020-07-28 8:57 ` [PATCH v2 5/5] perf test: Leader sampling shouldn't clear sample period Ian Rogers
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