| Message ID | 1541912383-19915-2-git-send-email-leo.yan@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | perf cs-etm: Correct packets handling | expand |
On Sun, Nov 11, 2018 at 12:59:39PM +0800, Leo Yan wrote: > 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. > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/util/cs-etm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > index 48ad217..fe18d7b 100644 > --- a/tools/perf/util/cs-etm.c > +++ b/tools/perf/util/cs-etm.c > @@ -997,7 +997,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) > } > > swap_packet: > - if (etmq->etm->synth_opts.last_branch) { > + if (etm->sample_branches || etmq->etm->synth_opts.last_branch) { This seems like the right thing to do, if only to be consistent with that is done in cs_etm__sample(). Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > /* > * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for > * the next incoming packet. > -- > 2.7.4 >
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 48ad217..fe18d7b 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -997,7 +997,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq) } swap_packet: - if (etmq->etm->synth_opts.last_branch) { + if (etm->sample_branches || etmq->etm->synth_opts.last_branch) { /* * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for * the next incoming packet.
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. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- tools/perf/util/cs-etm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.7.4