Commit 069dc2e4 authored by Namhyung Kim's avatar Namhyung Kim Committed by Zheng Zengkai
Browse files

perf arm-spe: Track task context switch for cpu-mode events 

mainline inclusion
from mainline-v5.16-rc1
commit 9dc9855f
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NGPV


CVE: NA

-------------------------------------------------

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.

Reviewed-by: default avatarLeo Yan <leo.yan@linaro.org>
Signed-off-by: default avatarGerman Gomez <german.gomez@arm.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20211111133625.193568-2-german.gomez@arm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarWei Li <liwei391@huawei.com>
Reviewed-by: default avatarYang Jihong <yangjihong1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 6faaf126

tools/perf/arch/arm64/util/arm-spe.c

+5 −1
Original line number Diff line number Diff line
@@ -251,8 +251,12 @@ 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;

}

tools/perf/util/arm-spe.c

+25 −0
Original line number Diff line number Diff line
@@ -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;