From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Leo Yan <leo.yan@linaro.org>
Cc: James Clark <james.clark@arm.com>,
John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Al Grant <Al.Grant@arm.com>
Subject: Re: [PATCH v1 2/3] perf arm-spe: Correct sample flags for dummy event
Date: Tue, 18 May 2021 09:54:02 -0300 [thread overview]
Message-ID: <YKO46nX17/GjqJjV@kernel.org> (raw)
In-Reply-To: <20210512152330.GA121227@leoy-ThinkPad-X240s>
Em Wed, May 12, 2021 at 11:23:30PM +0800, Leo Yan escreveu:
> On Wed, May 12, 2021 at 05:39:56PM +0300, James Clark wrote:
> >
> >
> > On 29/04/2021 18:00, Leo Yan wrote:
> > > The dummy event is mainly used for mmap, the TIME sample is only needed
> > > for per-cpu case so that the perf tool can rely on the correct timing
> > > for parsing symbols. And the CPU sample is useless for mmap.
> > >
> > > This patch enables TIME sample for per-cpu mmap and doesn't enable CPU
> > > sample. For later extension (e.g. support multiple AUX events), it sets
> > > the dummy event when the condition "opts->full_auxtrace" is true.
> > >
> > > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > > ---
> > > tools/perf/arch/arm64/util/arm-spe.c | 30 ++++++++++++++++------------
> > > 1 file changed, 17 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> > > index 902e73a64184..f6eec0900604 100644
> > > --- a/tools/perf/arch/arm64/util/arm-spe.c
> > > +++ b/tools/perf/arch/arm64/util/arm-spe.c
> > > @@ -70,7 +70,6 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> > > struct evsel *evsel, *arm_spe_evsel = NULL;
> > > struct perf_cpu_map *cpus = evlist->core.cpus;
> > > bool privileged = perf_event_paranoid_check(-1);
> > > - struct evsel *tracking_evsel;
> > > int err;
> > >
> > > sper->evlist = evlist;
> > > @@ -126,18 +125,23 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> > > evsel__set_sample_bit(arm_spe_evsel, CPU);
> > >
> > > /* Add dummy event to keep tracking */
> > > - err = parse_events(evlist, "dummy:u", NULL);
> > > - if (err)
> > > - return err;
> > > -
> > > - tracking_evsel = evlist__last(evlist);
> > > - evlist__set_tracking_event(evlist, tracking_evsel);
> > > -
> > > - tracking_evsel->core.attr.freq = 0;
> > > - tracking_evsel->core.attr.sample_period = 1;
> > > - evsel__set_sample_bit(tracking_evsel, TIME);
> > > - evsel__set_sample_bit(tracking_evsel, CPU);
> > > - evsel__reset_sample_bit(tracking_evsel, BRANCH_STACK);
> > > + if (opts->full_auxtrace) {
> > > + struct evsel *tracking_evsel;
> >
> > Hi Leo,
> >
> > I know the "if (opts->full_auxtrace)" pattern is copied from other auxtrace
> > files, but I don't think it does anything because there is this at the top
> > of the function:
> >
> > if (!opts->full_auxtrace)
> > return 0;
> >
> > The same applies for other usages of "full_auxtrace" in the same function.
> > They are all always true. I'm also not sure if it's ever defined what
> > full_auxtrace means.
>
> Good pointing. TBH, I also stuggled for handling "opts->full_auxtrace"
> when wrote the patch; IIUC, "opts->full_auxtrace" is also used in
> builtin-record.c to indicate if the recording contains AUX tracing.
>
> Will follow your suggestion to respin the patch (and refine the code)
> to remove the redundant condition checking for "opts->full_auxtrace".
Ok, so please collect his Tested-by and Reviewed-by and I'll wait for v2
then,
- Arnaldo
next prev parent reply other threads:[~2021-05-18 12:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 15:00 [PATCH v1 0/3] perf arm-spe: Correct recording configurations Leo Yan
2021-04-29 15:00 ` [PATCH v1 1/3] perf arm-spe: Correct sample flags for SPE event Leo Yan
2021-04-29 15:00 ` [PATCH v1 2/3] perf arm-spe: Correct sample flags for dummy event Leo Yan
2021-05-12 14:39 ` James Clark
2021-05-12 15:17 ` James Clark
2021-05-12 15:37 ` Leo Yan
2021-05-12 15:23 ` Leo Yan
2021-05-18 12:54 ` Arnaldo Carvalho de Melo [this message]
2021-05-18 14:18 ` Leo Yan
2021-04-29 15:01 ` [PATCH v1 3/3] perf arm-spe: Enable timestamp for per-cpu mode Leo Yan
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