* [PATCH v1 0/2] perf cs-etm: Improve timestamp tracing @ 2023-08-27 13:35 Leo Yan 2023-08-27 13:35 ` [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode Leo Yan 2023-08-27 13:35 ` [PATCH v1 2/2] perf cs-etm: Respect timestamp option Leo Yan 0 siblings, 2 replies; 6+ messages in thread From: Leo Yan @ 2023-08-27 13:35 UTC (permalink / raw) To: Arnaldo Carvalho de Melo, James Clark, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel Cc: Leo Yan This patch series is to improve timestamp handling in per-thread mode. The current code doesn't validate timestamp and always return success for per-thread mode, for a sane implementation, the first patch is to allow validation timestamp tracing in per-thread mode. The second patch is to respect timestamp option "--timestamp" or "-T", when users set this option, the tool will automatically enable hardware timestamp tracing in Arm CoreSight. Leo Yan (2): perf cs-etm: Validate timestamp tracing in per-thread mode perf cs-etm: Respect timestamp option tools/perf/arch/arm/util/cs-etm.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode 2023-08-27 13:35 [PATCH v1 0/2] perf cs-etm: Improve timestamp tracing Leo Yan @ 2023-08-27 13:35 ` Leo Yan 2023-09-04 15:23 ` James Clark 2023-08-27 13:35 ` [PATCH v1 2/2] perf cs-etm: Respect timestamp option Leo Yan 1 sibling, 1 reply; 6+ messages in thread From: Leo Yan @ 2023-08-27 13:35 UTC (permalink / raw) To: Arnaldo Carvalho de Melo, James Clark, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel Cc: Leo Yan So far, it's impossible to validate timestamp trace in Arm CoreSight when the perf is in the per-thread mode. E.g. for the command: perf record -e cs_etm/timestamp/ --per-thread -- ls The command enables config 'timestamp' for 'cs_etm' event in the per-thread mode. In this case, the function cs_etm_validate_config() directly bails out and skips validation. Given profiled process can be scheduled on any CPUs in the per-thread mode, this patch validates timestamp tracing for all CPUs when detect the CPU map is empty. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- tools/perf/arch/arm/util/cs-etm.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index b8d6a953fd74..cf9ef9ba800b 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -205,8 +205,17 @@ static int cs_etm_validate_config(struct auxtrace_record *itr, for (i = 0; i < cpu__max_cpu().cpu; i++) { struct perf_cpu cpu = { .cpu = i, }; - if (!perf_cpu_map__has(event_cpus, cpu) || - !perf_cpu_map__has(online_cpus, cpu)) + /* + * In per-cpu case, do the validation for CPUs to work with. + * In per-thread case, the CPU map is empty. Since the traced + * program can run on any CPUs in this case, thus don't skip + * validation. + */ + if (!perf_cpu_map__empty(event_cpus) && + !perf_cpu_map__has(event_cpus, cpu)) + continue; + + if (!perf_cpu_map__has(online_cpus, cpu)) continue; err = cs_etm_validate_context_id(itr, evsel, i); -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode 2023-08-27 13:35 ` [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode Leo Yan @ 2023-09-04 15:23 ` James Clark 2023-09-05 1:33 ` Leo Yan 0 siblings, 1 reply; 6+ messages in thread From: James Clark @ 2023-09-04 15:23 UTC (permalink / raw) To: Leo Yan Cc: Arnaldo Carvalho de Melo, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel On 27/08/2023 14:35, Leo Yan wrote: > So far, it's impossible to validate timestamp trace in Arm CoreSight when > the perf is in the per-thread mode. E.g. for the command: > > perf record -e cs_etm/timestamp/ --per-thread -- ls > > The command enables config 'timestamp' for 'cs_etm' event in the > per-thread mode. In this case, the function cs_etm_validate_config() > directly bails out and skips validation. > > Given profiled process can be scheduled on any CPUs in the per-thread > mode, this patch validates timestamp tracing for all CPUs when detect > the CPU map is empty. There is an edge case where the profiled process is known by the user to be pinned to a specific CPU, rather than possibly running on all CPUs, so this isn't always true. But I think that can be worked around by changing it to a per-cpu session to get around the new error. Given that this validation was only supposed to be best effort information and not get in the way you could say to not make it more restrictive. But it's quite a small edge case so either way: Reviewed-by: James Clark <james.clark@arm.com> > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/arch/arm/util/cs-etm.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c > index b8d6a953fd74..cf9ef9ba800b 100644 > --- a/tools/perf/arch/arm/util/cs-etm.c > +++ b/tools/perf/arch/arm/util/cs-etm.c > @@ -205,8 +205,17 @@ static int cs_etm_validate_config(struct auxtrace_record *itr, > for (i = 0; i < cpu__max_cpu().cpu; i++) { > struct perf_cpu cpu = { .cpu = i, }; > > - if (!perf_cpu_map__has(event_cpus, cpu) || > - !perf_cpu_map__has(online_cpus, cpu)) > + /* > + * In per-cpu case, do the validation for CPUs to work with. > + * In per-thread case, the CPU map is empty. Since the traced > + * program can run on any CPUs in this case, thus don't skip > + * validation. > + */ > + if (!perf_cpu_map__empty(event_cpus) && > + !perf_cpu_map__has(event_cpus, cpu)) > + continue; > + > + if (!perf_cpu_map__has(online_cpus, cpu)) > continue; > > err = cs_etm_validate_context_id(itr, evsel, i); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode 2023-09-04 15:23 ` James Clark @ 2023-09-05 1:33 ` Leo Yan 0 siblings, 0 replies; 6+ messages in thread From: Leo Yan @ 2023-09-05 1:33 UTC (permalink / raw) To: James Clark Cc: Arnaldo Carvalho de Melo, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel On Mon, Sep 04, 2023 at 04:23:43PM +0100, James Clark wrote: > > On 27/08/2023 14:35, Leo Yan wrote: > > So far, it's impossible to validate timestamp trace in Arm CoreSight when > > the perf is in the per-thread mode. E.g. for the command: > > > > perf record -e cs_etm/timestamp/ --per-thread -- ls > > > > The command enables config 'timestamp' for 'cs_etm' event in the > > per-thread mode. In this case, the function cs_etm_validate_config() > > directly bails out and skips validation. > > > > Given profiled process can be scheduled on any CPUs in the per-thread > > mode, this patch validates timestamp tracing for all CPUs when detect > > the CPU map is empty. > > There is an edge case where the profiled process is known by the user to > be pinned to a specific CPU, rather than possibly running on all CPUs, > so this isn't always true. Good point. However, when a process is pinned to specific CPUs, we still can dynamically change the scheduling affinity to any other CPUs by using taskset command or calling sched_setaffinity(). From a perf session's pespective, it is sane to validate timestamp tracing for all online CPUs for per-thread mode. > But I think that can be worked around by changing it to a per-cpu > session to get around the new error. Given that this validation was only > supposed to be best effort information and not get in the way you could > say to not make it more restrictive. > > But it's quite a small edge case so either way: > > Reviewed-by: James Clark <james.clark@arm.com> Thanks for review! Leo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v1 2/2] perf cs-etm: Respect timestamp option 2023-08-27 13:35 [PATCH v1 0/2] perf cs-etm: Improve timestamp tracing Leo Yan 2023-08-27 13:35 ` [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode Leo Yan @ 2023-08-27 13:35 ` Leo Yan 2023-09-04 15:25 ` James Clark 1 sibling, 1 reply; 6+ messages in thread From: Leo Yan @ 2023-08-27 13:35 UTC (permalink / raw) To: Arnaldo Carvalho de Melo, James Clark, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel Cc: Leo Yan When users pass the option '--timestamp' or '-T' in the record command, all events will set the PERF_SAMPLE_TIME bit in the attribution. In this case, the AUX event will record the kernel timestamp, but it doesn't mean Arm CoreSight enables timestamp packets in its hardware tracing. If the option '--timestamp' or '-T' is set, this patch always enables Arm CoreSight timestamp, as a result, the bit 28 in event's config is to be set. Before: # perf record -e cs_etm// --per-thread --timestamp -- ls # perf script --header-only ... # event : name = cs_etm//, , id = { 69 }, type = 12, size = 136, config = 0, { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 ... After: # perf record -e cs_etm// --per-thread --timestamp -- ls # perf script --header-only ... # event : name = cs_etm//, , id = { 49 }, type = 12, size = 136, config = 0x10000000, { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 ... Signed-off-by: Leo Yan <leo.yan@linaro.org> --- tools/perf/arch/arm/util/cs-etm.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index cf9ef9ba800b..58c506e9788d 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -442,6 +442,15 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, "contextid", 1); } + /* + * When the option '--timestamp' or '-T' is enabled, the PERF_SAMPLE_TIME + * bit is set for all events. In this case, always enable Arm CoreSight + * timestamp tracing. + */ + if (opts->sample_time_set) + evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel, + "timestamp", 1); + /* Add dummy event to keep tracking */ err = parse_event(evlist, "dummy:u"); if (err) -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v1 2/2] perf cs-etm: Respect timestamp option 2023-08-27 13:35 ` [PATCH v1 2/2] perf cs-etm: Respect timestamp option Leo Yan @ 2023-09-04 15:25 ` James Clark 0 siblings, 0 replies; 6+ messages in thread From: James Clark @ 2023-09-04 15:25 UTC (permalink / raw) To: Leo Yan Cc: Arnaldo Carvalho de Melo, Suzuki K Poulose, Mike Leach, John Garry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa, Namhyung Kim, Ian Rogers, Adrian Hunter, coresight, linux-arm-kernel, linux-perf-users, linux-kernel On 27/08/2023 14:35, Leo Yan wrote: > When users pass the option '--timestamp' or '-T' in the record command, > all events will set the PERF_SAMPLE_TIME bit in the attribution. In > this case, the AUX event will record the kernel timestamp, but it > doesn't mean Arm CoreSight enables timestamp packets in its hardware > tracing. > > If the option '--timestamp' or '-T' is set, this patch always enables > Arm CoreSight timestamp, as a result, the bit 28 in event's config is to > be set. > > Before: > > # perf record -e cs_etm// --per-thread --timestamp -- ls > # perf script --header-only > ... > # event : name = cs_etm//, , id = { 69 }, type = 12, size = 136, > config = 0, { sample_period, sample_freq } = 1, > sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, > disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 > ... > > After: > > # perf record -e cs_etm// --per-thread --timestamp -- ls > # perf script --header-only > ... > # event : name = cs_etm//, , id = { 49 }, type = 12, size = 136, > config = 0x10000000, { sample_period, sample_freq } = 1, > sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST, > disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1 > ... > > Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: James Clark <james.clark@arm.com> > --- > tools/perf/arch/arm/util/cs-etm.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c > index cf9ef9ba800b..58c506e9788d 100644 > --- a/tools/perf/arch/arm/util/cs-etm.c > +++ b/tools/perf/arch/arm/util/cs-etm.c > @@ -442,6 +442,15 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, > "contextid", 1); > } > > + /* > + * When the option '--timestamp' or '-T' is enabled, the PERF_SAMPLE_TIME > + * bit is set for all events. In this case, always enable Arm CoreSight > + * timestamp tracing. > + */ > + if (opts->sample_time_set) > + evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel, > + "timestamp", 1); > + > /* Add dummy event to keep tracking */ > err = parse_event(evlist, "dummy:u"); > if (err) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-09-05 1:34 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-08-27 13:35 [PATCH v1 0/2] perf cs-etm: Improve timestamp tracing Leo Yan 2023-08-27 13:35 ` [PATCH v1 1/2] perf cs-etm: Validate timestamp tracing in per-thread mode Leo Yan 2023-09-04 15:23 ` James Clark 2023-09-05 1:33 ` Leo Yan 2023-08-27 13:35 ` [PATCH v1 2/2] perf cs-etm: Respect timestamp option Leo Yan 2023-09-04 15:25 ` James Clark
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