From: Leo Yan Date: Tue, 11 Dec 2018 07:38:21 +0000 (+0800) Subject: perf cs-etm: Correct packets swapping in cs_etm__flush() X-Git-Tag: v5.4-rc1~1977^2^2~37 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=43fd56669c28cd354e9228bdb58e4bca1c1a8b66;p=platform%2Fkernel%2Flinux-rpi.git perf cs-etm: Correct packets swapping in cs_etm__flush() The structure cs_etm_queue uses 'prev_packet' to point to previous packet, this can be used to combine with new coming packet to generate samples. In function cs_etm__flush() it swaps packets only when the flag 'etm->synth_opts.last_branch' is true, this means that it will not swap packets if without option '--itrace=il' to generate last branch entries; thus for this case the 'prev_packet' doesn't point to the correct previous packet and the stale packet still will be used to generate sequential sample. Thus if dump trace with 'perf script' command we can see the incorrect flow with the stale packet's address info. This patch corrects packets swapping in cs_etm__flush(); except using the flag 'etm->synth_opts.last_branch' it also checks the another flag 'etm->sample_branches', if any flag is true then it swaps packets so can save correct content to 'prev_packet'. Finally this can fix the wrong program flow dumping issue. The patch has a minor refactoring to use 'etm->synth_opts.last_branch' instead of 'etmq->etm->synth_opts.last_branch' for condition checking, this is consistent with that is done in cs_etm__sample(). Signed-off-by: Leo Yan Reviewed-by: Mathieu Poirier Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Mike Leach Cc: Namhyung Kim Cc: Robert Walker Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1544513908-16805-2-git-send-email-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 23159c33..789707b 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1042,7 +1042,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) } swap_packet: - if (etmq->etm->synth_opts.last_branch) { + if (etm->sample_branches || etm->synth_opts.last_branch) { /* * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for * the next incoming packet.