Subject: [PATCH 15/21] perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet

From: [email-masked] (Arnaldo Carvalho de Melo)
Date: Wed, 1 Aug 2018 18:36:42 -0300

From: Leo Yan <[email-masked]>

CS_ETM_TRACE_ON packet itself can give the info that there have a
discontinuity in the trace, this patch is to add branch sample for
CS_ETM_TRACE_ON packet if it is inserted in the middle of CS_ETM_RANGE
packets; as result we can have hint for the trace discontinuity.

Signed-off-by: Leo Yan <[email-masked]>
Reviewed-by: Mathieu Poirier <[email-masked]>
Cc: Alexander Shishkin <[email-masked]>
Cc: Jiri Olsa <[email-masked]>
Cc: Kim Phillips <[email-masked]>
Cc: Mike Leach <[email-masked]>
Cc: Namhyung Kim <[email-masked]>
Cc: Peter Zijlstra <[email-masked]>
Cc: Robert Walker <[email-masked]>
Cc: linux-arm-kernel at lists.infradead.org
Link: http://lkml.kernel.org/r/1531295145-596-7-git-send-email-leo.yan at linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <[email-masked]>
---
 tools/perf/util/cs-etm.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index d3b794286bca..2ae640257fdb 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -910,13 +910,23 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
 		etmq->period_instructions = instrs_over;
 	}
 
-	if (etm->sample_branches &&
-	    etmq->prev_packet &&
-	    etmq->prev_packet->sample_type == CS_ETM_RANGE &&
-	    etmq->prev_packet->last_instr_taken_branch) {
-		ret = cs_etm__synth_branch_sample(etmq);
-		if (ret)
-			return ret;
+	if (etm->sample_branches && etmq->prev_packet) {
+		bool generate_sample = false;
+
+		/* Generate sample for tracing on packet */
+		if (etmq->prev_packet->sample_type == CS_ETM_TRACE_ON)
+			generate_sample = true;
+
+		/* Generate sample for branch taken packet */
+		if (etmq->prev_packet->sample_type == CS_ETM_RANGE &&
+		    etmq->prev_packet->last_instr_taken_branch)
+			generate_sample = true;
+
+		if (generate_sample) {
+			ret = cs_etm__synth_branch_sample(etmq);
+			if (ret)
+				return ret;
+		}
 	}
 
 	if (etm->sample_branches || etm->synth_opts.last_branch) {
-- 
2.14.4