linux-kernel - [RFC PATCH 2/5] perf cs-etm: Only search timestamp in current sample's queue.

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Date:   Tue,  9 Feb 2021 11:58:54 +0200
From:   James Clark <james.clark@....com>
To:     coresight@...ts.linaro.org
Cc:     al.grant@....com, branislav.rankov@....com, denik@...omium.org,
        James Clark <james.clark@....com>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        Mike Leach <mike.leach@...aro.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 2/5] perf cs-etm: Only search timestamp in current sample's queue.

Change initial timestamp search to only operate on the queue
related to the current event. In a later change the bounds
of the aux record will also be used to reset the decoder and
the record is only relevant to a single queue.

This doesn't work --per-thread mode where cpu == -1 so
a further change will be required.

Also this change makes some files that had coresight data
but didn't syntesise any events start working and generating
events. I'm not sure of the reason for that. I'd expect this
change to only affect the ordering of events.

Signed-off-by: James Clark <james.clark@....com>
---
 tools/perf/util/cs-etm.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 440001cdd3b8..9ebe43d60d1e 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -97,7 +97,7 @@ struct cs_etm_queue {
 /* RB tree for quick conversion between traceID and metadata pointers */
 static struct intlist *traceid_list;
 
-static int cs_etm__update_queues(struct cs_etm_auxtrace *etm);
+static int cs_etm__update_queues(struct cs_etm_auxtrace *etm, int cpu);
 static int cs_etm__process_queues(struct cs_etm_auxtrace *etm);
 static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
 					   pid_t tid);
@@ -524,7 +524,7 @@ static void cs_etm__dump_event(struct cs_etm_auxtrace *etm,
 static int cs_etm__flush_events(struct perf_session *session,
 				struct perf_tool *tool)
 {
-	int ret;
+	//int ret;
 	struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
 						   struct cs_etm_auxtrace,
 						   auxtrace);
@@ -534,10 +534,12 @@ static int cs_etm__flush_events(struct perf_session *session,
 	if (!tool->ordered_events)
 		return -EINVAL;
 
-	ret = cs_etm__update_queues(etm);
+	// TODO: does this need to be here? It is already called in cs_etm__process_event
+	//       when the aux records are available.
+	//ret = cs_etm__update_queues(etm);
 
-	if (ret < 0)
-		return ret;
+	//if (ret < 0)
+	//	return ret;
 
 	if (etm->timeless_decoding)
 		return cs_etm__process_timeless_queues(etm, -1);
@@ -851,10 +853,7 @@ static int cs_etm__setup_queue(struct cs_etm_auxtrace *etm,
 	etmq->queue_nr = queue_nr;
 	etmq->offset = 0;
 
-	if (etm->timeless_decoding)
-		return 0;
-	else
-		return cs_etm__seach_first_timestamp(etmq);
+	return 0;
 }
 
 static int cs_etm__setup_queues(struct cs_etm_auxtrace *etm)
@@ -874,14 +873,20 @@ static int cs_etm__setup_queues(struct cs_etm_auxtrace *etm)
 	return 0;
 }
 
-static int cs_etm__update_queues(struct cs_etm_auxtrace *etm)
+static int cs_etm__update_queues(struct cs_etm_auxtrace *etm, int cpu)
 {
+	int ret;
 	if (etm->queues.new_data) {
 		etm->queues.new_data = false;
-		return cs_etm__setup_queues(etm);
+		ret = cs_etm__setup_queues(etm);
+		if (ret)
+			return ret;
 	}
 
-	return 0;
+	if (!etm->timeless_decoding)
+		return cs_etm__seach_first_timestamp(etm->queues.queue_array[cpu].priv);
+	else
+		return 0;
 }
 
 static inline
@@ -2358,8 +2363,9 @@ static int cs_etm__process_event(struct perf_session *session,
 	else
 		timestamp = 0;
 
-	if (timestamp || etm->timeless_decoding) {
-		err = cs_etm__update_queues(etm);
+	if ((timestamp || etm->timeless_decoding)
+			&& event->header.type == PERF_RECORD_AUX) {
+		err = cs_etm__update_queues(etm, sample->cpu);
 		if (err)
 			return err;
 	}
-- 
2.28.0