From: Mathieu Poirier <mathieu.poirier@linaro.org> To: James Clark <james.clark@arm.com> Cc: coresight@lists.linaro.org, al.grant@arm.com, branislav.rankov@arm.com, denik@chromium.org, suzuki.poulose@arm.com, Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>, John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] perf cs-etm: Set time on synthesised samples to preserve ordering Date: Thu, 15 Apr 2021 13:54:16 -0600 [thread overview] Message-ID: <20210415195416.GB937505@xps15> (raw) In-Reply-To: <20210414143919.12605-2-james.clark@arm.com> On Wed, Apr 14, 2021 at 05:39:19PM +0300, James Clark wrote: > The following attribute is set when synthesising samples in > timed decoding mode: > > attr.sample_type |= PERF_SAMPLE_TIME; > > This results in new samples that appear to have timestamps but > because we don't assign any timestamps to the samples, when the > resulting inject file is opened again, the synthesised samples > will be on the wrong side of the MMAP or COMM events. > I understand the problem. Once again an issue caused by CS and the kernel having a different view of time. > For example this results in the samples being associated with > the perf binary, rather than the target of the record: > > perf record -e cs_etm/@tmc_etr0/u top > perf inject -i perf.data -o perf.inject --itrace=i100il > perf report -i perf.inject > > Where 'Command' == perf should show as 'top': > > # Overhead Command Source Shared Object Source Symbol Target Symbol Basic Block Cycles > # ........ ....... .................... ...................... ...................... .................. > # > 31.08% perf [unknown] [.] 0x000000000040c3f8 [.] 0x000000000040c3e8 - > > If the perf.data file is opened directly with perf, without the > inject step, then this already works correctly because the > events are synthesised after the COMM and MMAP events and > no second sorting happens. Re-sorting only happens when opening > the perf.inject file for the second time so timestamps are > needed. > > Using the timestamp from the AUX record mirrors the current > behaviour when opening directly with perf, because the events > are generated on the call to cs_etm__process_queues(). > > Signed-off-by: James Clark <james.clark@arm.com> > Co-developed-by: Al Grant <al.grant@arm.com> > Signed-off-by: Al Grant <al.grant@arm.com> Suzuki is correct, your name has to appear after Al's. > --- > tools/perf/util/cs-etm.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > index c25da2ffa8f3..d0fa9dce47f1 100644 > --- a/tools/perf/util/cs-etm.c > +++ b/tools/perf/util/cs-etm.c > @@ -54,6 +54,7 @@ struct cs_etm_auxtrace { > u8 sample_instructions; > > int num_cpu; > + u64 latest_kernel_timestamp; > u32 auxtrace_type; > u64 branches_sample_type; > u64 branches_id; > @@ -1192,6 +1193,8 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq, > event->sample.header.misc = cs_etm__cpu_mode(etmq, addr); > event->sample.header.size = sizeof(struct perf_event_header); > > + if (!etm->timeless_decoding) > + sample.time = etm->latest_kernel_timestamp; > sample.ip = addr; > sample.pid = tidq->pid; > sample.tid = tidq->tid; > @@ -1248,6 +1251,8 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq, > event->sample.header.misc = cs_etm__cpu_mode(etmq, ip); > event->sample.header.size = sizeof(struct perf_event_header); > > + if (!etm->timeless_decoding) > + sample.time = etm->latest_kernel_timestamp; > sample.ip = ip; > sample.pid = tidq->pid; > sample.tid = tidq->tid; > @@ -2412,9 +2417,10 @@ static int cs_etm__process_event(struct perf_session *session, > else if (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE) > return cs_etm__process_switch_cpu_wide(etm, event); > > - if (!etm->timeless_decoding && > - event->header.type == PERF_RECORD_AUX) > + if (!etm->timeless_decoding && event->header.type == PERF_RECORD_AUX) { > + etm->latest_kernel_timestamp = sample_kernel_timestamp; It will be fun to fix this when 8.4 comes out but for now it's the best we've got. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > return cs_etm__process_queues(etm); > + } > > return 0; > } > -- > 2.28.0 >
WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Poirier <mathieu.poirier@linaro.org> To: James Clark <james.clark@arm.com> Cc: coresight@lists.linaro.org, al.grant@arm.com, branislav.rankov@arm.com, denik@chromium.org, suzuki.poulose@arm.com, Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>, John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] perf cs-etm: Set time on synthesised samples to preserve ordering Date: Thu, 15 Apr 2021 13:54:16 -0600 [thread overview] Message-ID: <20210415195416.GB937505@xps15> (raw) In-Reply-To: <20210414143919.12605-2-james.clark@arm.com> On Wed, Apr 14, 2021 at 05:39:19PM +0300, James Clark wrote: > The following attribute is set when synthesising samples in > timed decoding mode: > > attr.sample_type |= PERF_SAMPLE_TIME; > > This results in new samples that appear to have timestamps but > because we don't assign any timestamps to the samples, when the > resulting inject file is opened again, the synthesised samples > will be on the wrong side of the MMAP or COMM events. > I understand the problem. Once again an issue caused by CS and the kernel having a different view of time. > For example this results in the samples being associated with > the perf binary, rather than the target of the record: > > perf record -e cs_etm/@tmc_etr0/u top > perf inject -i perf.data -o perf.inject --itrace=i100il > perf report -i perf.inject > > Where 'Command' == perf should show as 'top': > > # Overhead Command Source Shared Object Source Symbol Target Symbol Basic Block Cycles > # ........ ....... .................... ...................... ...................... .................. > # > 31.08% perf [unknown] [.] 0x000000000040c3f8 [.] 0x000000000040c3e8 - > > If the perf.data file is opened directly with perf, without the > inject step, then this already works correctly because the > events are synthesised after the COMM and MMAP events and > no second sorting happens. Re-sorting only happens when opening > the perf.inject file for the second time so timestamps are > needed. > > Using the timestamp from the AUX record mirrors the current > behaviour when opening directly with perf, because the events > are generated on the call to cs_etm__process_queues(). > > Signed-off-by: James Clark <james.clark@arm.com> > Co-developed-by: Al Grant <al.grant@arm.com> > Signed-off-by: Al Grant <al.grant@arm.com> Suzuki is correct, your name has to appear after Al's. > --- > tools/perf/util/cs-etm.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > index c25da2ffa8f3..d0fa9dce47f1 100644 > --- a/tools/perf/util/cs-etm.c > +++ b/tools/perf/util/cs-etm.c > @@ -54,6 +54,7 @@ struct cs_etm_auxtrace { > u8 sample_instructions; > > int num_cpu; > + u64 latest_kernel_timestamp; > u32 auxtrace_type; > u64 branches_sample_type; > u64 branches_id; > @@ -1192,6 +1193,8 @@ static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq, > event->sample.header.misc = cs_etm__cpu_mode(etmq, addr); > event->sample.header.size = sizeof(struct perf_event_header); > > + if (!etm->timeless_decoding) > + sample.time = etm->latest_kernel_timestamp; > sample.ip = addr; > sample.pid = tidq->pid; > sample.tid = tidq->tid; > @@ -1248,6 +1251,8 @@ static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq, > event->sample.header.misc = cs_etm__cpu_mode(etmq, ip); > event->sample.header.size = sizeof(struct perf_event_header); > > + if (!etm->timeless_decoding) > + sample.time = etm->latest_kernel_timestamp; > sample.ip = ip; > sample.pid = tidq->pid; > sample.tid = tidq->tid; > @@ -2412,9 +2417,10 @@ static int cs_etm__process_event(struct perf_session *session, > else if (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE) > return cs_etm__process_switch_cpu_wide(etm, event); > > - if (!etm->timeless_decoding && > - event->header.type == PERF_RECORD_AUX) > + if (!etm->timeless_decoding && event->header.type == PERF_RECORD_AUX) { > + etm->latest_kernel_timestamp = sample_kernel_timestamp; It will be fun to fix this when 8.4 comes out but for now it's the best we've got. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > return cs_etm__process_queues(etm); > + } > > return 0; > } > -- > 2.28.0 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-04-15 19:54 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-14 14:39 [PATCH 1/2] perf cs-etm: Refactor timestamp variable names James Clark 2021-04-14 14:39 ` James Clark 2021-04-14 14:39 ` [PATCH 2/2] perf cs-etm: Set time on synthesised samples to preserve ordering James Clark 2021-04-14 14:39 ` James Clark 2021-04-14 14:41 ` James Clark 2021-04-14 14:41 ` James Clark 2021-04-15 12:39 ` Leo Yan 2021-04-15 12:39 ` Leo Yan 2021-04-15 12:51 ` James Clark 2021-04-15 12:51 ` James Clark 2021-04-15 14:33 ` Leo Yan 2021-04-15 14:33 ` Leo Yan 2021-04-16 9:55 ` James Clark 2021-04-16 9:55 ` James Clark 2021-04-14 15:54 ` Suzuki K Poulose 2021-04-14 15:54 ` Suzuki K Poulose 2021-04-15 12:30 ` Leo Yan 2021-04-15 12:30 ` Leo Yan 2021-04-15 19:54 ` Mathieu Poirier [this message] 2021-04-15 19:54 ` Mathieu Poirier 2021-04-16 10:16 ` James Clark 2021-04-16 10:16 ` James Clark 2021-04-15 19:46 ` [PATCH 1/2] perf cs-etm: Refactor timestamp variable names Mathieu Poirier 2021-04-15 19:46 ` Mathieu Poirier
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