Re: [PATCH 1/3] perf arm-spe: Track task context switch for cpu-mode events

On 06/11/2021 19:49, Arnaldo Carvalho de Melo wrote:

Em Sat, Nov 06, 2021 at 11:29:07AM +0800, Leo Yan escreveu:

quoted

[...]
Reviewed-by: Leo Yan <redacted>

Note for one thing, please keep "Namhyung Kim" as the author for this
patch, thanks.

This merits a v2 submission, please do so.

- Arnaldo
 

Will do,

Also will fix the authorship of [2/3].

Thanks,
German

quoted

Leo

quoted

---
 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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