[tip:perf/core] perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet

From: tip-bot for Leo Yan
Date: Thu Aug 02 2018 - 12:02:41 EST


Commit-ID: 14a85b1eca348e00a9f209b522f94ec3ead94acb
Gitweb: https://git.kernel.org/tip/14a85b1eca348e00a9f209b522f94ec3ead94acb
Author: Leo Yan <leo.yan@xxxxxxxxxx>
AuthorDate: Wed, 11 Jul 2018 15:45:45 +0800
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kim Phillips <kim.phillips@xxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Robert Walker <robert.walker@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1531295145-596-7-git-send-email-leo.yan@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
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) {