linux-kernel - [tip:perf/core] perf cs-etm: Generate branch sample for CS_ETM_TRACE

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Message-ID: <tip-14a85b1eca348e00a9f209b522f94ec3ead94acb@git.kernel.org>
Date:   Thu, 2 Aug 2018 01:14:39 -0700
From:   tip-bot for Leo Yan <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, peterz@...radead.org,
        alexander.shishkin@...ux.intel.com, leo.yan@...aro.org,
        jolsa@...hat.com, namhyung@...nel.org,
        linux-kernel@...r.kernel.org, tglx@...utronix.de,
        mathieu.poirier@...aro.org, acme@...hat.com, robert.walker@....com,
        mike.leach@...aro.org, hpa@...or.com, kim.phillips@....com
Subject: [tip:perf/core] perf cs-etm: Generate branch sample for
 CS_ETM_TRACE_ON packet

Commit-ID:  14a85b1eca348e00a9f209b522f94ec3ead94acb
Gitweb:     https://git.kernel.org/tip/14a85b1eca348e00a9f209b522f94ec3ead94acb
Author:     Leo Yan <leo.yan@...aro.org>
AuthorDate: Wed, 11 Jul 2018 15:45:45 +0800
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Tue, 31 Jul 2018 11:22:50 -0300

perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet

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 <leo.yan@...aro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Kim Phillips <kim.phillips@....com>
Cc: Mike Leach <mike.leach@...aro.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Robert Walker <robert.walker@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Link: http://lkml.kernel.org/r/1531295145-596-7-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 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) {