Commit 1ae431bf authored by German Gomez's avatar German Gomez Committed by Zheng Zengkai
Browse files

perf arm-spe: Support hardware-based PID tracing 

mainline inclusion
from mainline-v5.16-rc1
commit 27d113cf
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NGPV
CVE: NA

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

If ARM SPE traces contains CONTEXT packets with TID info, use these
values for tracking the TID of samples. Otherwise fall back to using
context switch events and display a message warning to the user of
possible timing inaccuracies [1].

[1] https://lore.kernel.org/lkml/f877cfa6-9b25-6445-3806-ca44a4042eaf@arm.com/



Signed-off-by: default avatarGerman Gomez <german.gomez@arm.com>
Acked-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: Leo Yan <leo.yan@linaro.org>
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/20211111133625.193568-5-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 e0165826

tools/perf/util/arm-spe.c

+70 −29
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct arm_spe { 
	u64				kernel_start;



	unsigned long			num_events;

	u8				use_ctx_pkt_for_pid;

};



struct arm_spe_queue {
@@ -226,6 +227,44 @@ static inline u8 arm_spe_cpumode(struct arm_spe *spe, u64 ip) 
		PERF_RECORD_MISC_USER;

}



static void arm_spe_set_pid_tid_cpu(struct arm_spe *spe,

				    struct auxtrace_queue *queue)

{

	struct arm_spe_queue *speq = queue->priv;

	pid_t tid;



	tid = machine__get_current_tid(spe->machine, speq->cpu);

	if (tid != -1) {

		speq->tid = tid;

		thread__zput(speq->thread);

	} else

		speq->tid = queue->tid;



	if ((!speq->thread) && (speq->tid != -1)) {

		speq->thread = machine__find_thread(spe->machine, -1,

						    speq->tid);

	}



	if (speq->thread) {

		speq->pid = speq->thread->pid_;

		if (queue->cpu == -1)

			speq->cpu = speq->thread->cpu;

	}

}



static int arm_spe_set_tid(struct arm_spe_queue *speq, pid_t tid)

{

	struct arm_spe *spe = speq->spe;

	int err = machine__set_current_tid(spe->machine, speq->cpu, -1, tid);



	if (err)

		return err;



	arm_spe_set_pid_tid_cpu(spe, &spe->queues.queue_array[speq->queue_nr]);



	return 0;

}



static void arm_spe_prep_sample(struct arm_spe *spe,

				struct arm_spe_queue *speq,

				union perf_event *event,
@@ -460,6 +499,19 @@ static int arm_spe_run_decoder(struct arm_spe_queue *speq, u64 *timestamp) 
		 * can correlate samples between Arm SPE trace data and other

		 * perf events with correct time ordering.

		 */



		/*

		 * Update pid/tid info.

		 */

		record = &speq->decoder->record;

		if (!spe->timeless_decoding && record->context_id != (u64)-1) {

			ret = arm_spe_set_tid(speq, record->context_id);

			if (ret)

				return ret;



			spe->use_ctx_pkt_for_pid = true;

		}



		ret = arm_spe_sample(speq);

		if (ret)

			return ret;
@@ -586,31 +638,6 @@ static bool arm_spe__is_timeless_decoding(struct arm_spe *spe) 
	return timeless_decoding;

}



static void arm_spe_set_pid_tid_cpu(struct arm_spe *spe,

				    struct auxtrace_queue *queue)

{

	struct arm_spe_queue *speq = queue->priv;

	pid_t tid;



	tid = machine__get_current_tid(spe->machine, speq->cpu);

	if (tid != -1) {

		speq->tid = tid;

		thread__zput(speq->thread);

	} else

		speq->tid = queue->tid;



	if ((!speq->thread) && (speq->tid != -1)) {

		speq->thread = machine__find_thread(spe->machine, -1,

						    speq->tid);

	}



	if (speq->thread) {

		speq->pid = speq->thread->pid_;

		if (queue->cpu == -1)

			speq->cpu = speq->thread->cpu;

	}

}



static int arm_spe_process_queues(struct arm_spe *spe, u64 timestamp)

{

	unsigned int queue_nr;
@@ -641,6 +668,11 @@ static int arm_spe_process_queues(struct arm_spe *spe, u64 timestamp) 
			ts = timestamp;

		}



		/*

		 * A previous context-switch event has set pid/tid in the machine's context, so

		 * here we need to update the pid/tid in the thread and SPE queue.

		 */

		if (!spe->use_ctx_pkt_for_pid)

			arm_spe_set_pid_tid_cpu(spe, queue);



		ret = arm_spe_run_decoder(speq, &ts);
@@ -740,8 +772,9 @@ static int arm_spe_process_event(struct perf_session *session, 
		if (err)

			return err;



		if (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE ||

		    event->header.type == PERF_RECORD_SWITCH)

		if (!spe->use_ctx_pkt_for_pid &&

		    (event->header.type == PERF_RECORD_SWITCH_CPU_WIDE ||

		    event->header.type == PERF_RECORD_SWITCH))

			err = arm_spe_context_switch(spe, event, sample);

	}
@@ -808,7 +841,15 @@ static int arm_spe_flush(struct perf_session *session __maybe_unused, 
		return arm_spe_process_timeless_queues(spe, -1,

				MAX_TIMESTAMP - 1);



	return arm_spe_process_queues(spe, MAX_TIMESTAMP);

	ret = arm_spe_process_queues(spe, MAX_TIMESTAMP);

	if (ret)

		return ret;



	if (!spe->use_ctx_pkt_for_pid)

		ui__warning("Arm SPE CONTEXT packets not found in the traces.\n"

			    "Matching of TIDs to SPE events could be inaccurate.\n");



	return 0;

}



static void arm_spe_free_queue(void *priv)