Messages in this thread Patch in this message | | | Date | Sat, 6 Nov 2021 11:29:07 +0800 | From | Leo Yan <> | Subject | Re: [PATCH 1/3] perf arm-spe: Track task context switch for cpu-mode events |
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Hi German,
On Tue, Nov 02, 2021 at 06:07:37PM +0000, German Gomez wrote: > When perf report synthesize events from ARM SPE data, it refers to > current cpu, pid and tid in the machine. But there's no place to set > them in the ARM SPE decoder. I'm seeing all pid/tid is set to -1 and > user symbols are not resolved in the output. > > # perf record -a -e arm_spe_0/ts_enable=1/ sleep 1 > > # perf report -q | head > 8.77% 8.77% :-1 [kernel.kallsyms] [k] format_decode > 7.02% 7.02% :-1 [kernel.kallsyms] [k] seq_printf > 7.02% 7.02% :-1 [unknown] [.] 0x0000ffff9f687c34 > 5.26% 5.26% :-1 [kernel.kallsyms] [k] vsnprintf > 3.51% 3.51% :-1 [kernel.kallsyms] [k] string > 3.51% 3.51% :-1 [unknown] [.] 0x0000ffff9f66ae20 > 3.51% 3.51% :-1 [unknown] [.] 0x0000ffff9f670b3c > 3.51% 3.51% :-1 [unknown] [.] 0x0000ffff9f67c040 > 1.75% 1.75% :-1 [kernel.kallsyms] [k] ___cache_free > 1.75% 1.75% :-1 [kernel.kallsyms] [k] > __count_memcg_events > > Like Intel PT, add context switch records to track task info. As ARM > SPE support was added later than PERF_RECORD_SWITCH_CPU_WIDE, I think > we can safely set the attr.context_switch bit and use it. > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > Signed-off-by: German Gomez <german.gomez@arm.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Note for one thing, please keep "Namhyung Kim" as the author for this patch, thanks.
Leo
> --- > tools/perf/arch/arm64/util/arm-spe.c | 6 +++++- > tools/perf/util/arm-spe.c | 25 +++++++++++++++++++++++++ > 2 files changed, 30 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c > index a4420d4df..58ba8d15c 100644 > --- a/tools/perf/arch/arm64/util/arm-spe.c > +++ b/tools/perf/arch/arm64/util/arm-spe.c > @@ -166,8 +166,12 @@ static int arm_spe_recording_options(struct auxtrace_record *itr, > tracking_evsel->core.attr.sample_period = 1; > > /* In per-cpu case, always need the time of mmap events etc */ > - if (!perf_cpu_map__empty(cpus)) > + if (!perf_cpu_map__empty(cpus)) { > evsel__set_sample_bit(tracking_evsel, TIME); > + evsel__set_sample_bit(tracking_evsel, CPU); > + /* also track task context switch */ > + tracking_evsel->core.attr.context_switch = 1; > + } > > return 0; > } > diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c > index 58b7069c5..230bc7ab2 100644 > --- a/tools/perf/util/arm-spe.c > +++ b/tools/perf/util/arm-spe.c > @@ -681,6 +681,25 @@ static int arm_spe_process_timeless_queues(struct arm_spe *spe, pid_t tid, > return 0; > } > > +static int arm_spe_context_switch(struct arm_spe *spe, union perf_event *event, > + struct perf_sample *sample) > +{ > + pid_t pid, tid; > + int cpu; > + > + if (!(event->header.misc & PERF_RECORD_MISC_SWITCH_OUT)) > + return 0; > + > + pid = event->context_switch.next_prev_pid; > + tid = event->context_switch.next_prev_tid; > + cpu = sample->cpu; > + > + if (tid == -1) > + pr_warning("context_switch event has no tid\n"); > + > + return machine__set_current_tid(spe->machine, cpu, pid, tid); > +} > + > static int arm_spe_process_event(struct perf_session *session, > union perf_event *event, > struct perf_sample *sample, > @@ -718,6 +737,12 @@ static int arm_spe_process_event(struct perf_session *session, > } > } else if (timestamp) { > err = arm_spe_process_queues(spe, timestamp); > + if (err) > + return err; > + > + if (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE || > + event->header.type == PERF_RECORD_SWITCH) > + err = arm_spe_context_switch(spe, event, sample); > } > > return err; > -- > 2.25.1 >
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