From: Leo Yan <leo.yan@linaro.org>
To: James Clark <james.clark@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Al Grant <Al.Grant@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>,
Adrian Hunter <adrian.hunter@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 4/6] perf arm-spe: Assign kernel time to synthesized event
Date: Fri, 16 Apr 2021 21:21:04 +0800 [thread overview]
Message-ID: <20210416132104.GG1011890@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <c9c060d1-0884-b67d-7689-6b45ad10baa9@arm.com>
On Fri, Apr 16, 2021 at 03:51:25PM +0300, James Clark wrote:
[...]
> >> I noticed that in arm_spe_recording_options() the TIME sample bit is set regardless of any options.
> >> I don't know of a way to remove this, and if there isn't, does that mean that all the code in this
> >> file that looks at spe->timeless_decoding is untested and has never been hit?
> >>
> >> Unless there is a way to get a perf file with only the AUXTRACE event and no others? I think that one
> >> might have no timestamp set. Otherwise other events will always have timestamps so spe->timeless_decoding
> >> is always false.
> >
> > Good point. To be honest, I never noticed this issue until you
> > mentioned this.
> >
> > We should fix for the "timeless" flow; and it's questionable for the
> > function arm_spe_recording_options(), except for setting
> > PERF_SAMPLE_TIME, it also hard codes for setting
> > PERF_SAMPLE_CPU and PERF_SAMPLE_TID. Might need to carefully go
> > through this function.
> >
>
> Yeah, it's not strictly related to your change, which is definitely an improvement.
> But maybe we should have a look at the SPE implementation relating to timestamps as a whole.
Totally agree, at least this patch series should not introduce any
barrier for timeless case. I will go back to verify it; if you'd
like to fix timeless issue, please feel free to go ahead.
Thanks,
Leo
next prev parent reply other threads:[~2021-04-16 13:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-12 9:10 [PATCH v4 0/6] perf arm-spe: Enable timestamp Leo Yan
2021-04-12 9:10 ` [PATCH v4 1/6] perf arm-spe: Remove unused enum value ARM_SPE_PER_CPU_MMAPS Leo Yan
2021-04-15 14:13 ` James Clark
2021-04-15 14:41 ` Leo Yan
2021-04-15 14:49 ` James Clark
2021-04-12 9:10 ` [PATCH v4 2/6] perf arm-spe: Save clock parameters from TIME_CONV event Leo Yan
2021-04-12 9:10 ` [PATCH v4 3/6] perf arm-spe: Convert event kernel time to counter value Leo Yan
2021-04-12 9:10 ` [PATCH v4 4/6] perf arm-spe: Assign kernel time to synthesized event Leo Yan
2021-04-15 14:46 ` James Clark
2021-04-15 15:23 ` Leo Yan
2021-04-16 12:51 ` James Clark
2021-04-16 13:21 ` Leo Yan [this message]
2021-04-29 15:23 ` Leo Yan
2021-04-12 9:10 ` [PATCH v4 5/6] perf arm-spe: Bail out if the trace is later than perf event Leo Yan
2021-04-12 9:10 ` [PATCH v4 6/6] perf arm-spe: Don't wait for PERF_RECORD_EXIT event Leo Yan
2021-04-15 14:43 ` [PATCH v4 0/6] perf arm-spe: Enable timestamp James Clark
2021-04-15 14:56 ` Leo Yan
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