Messages in this thread | | | Date | Mon, 31 Aug 2020 14:38:32 -0600 | From | Mathieu Poirier <> | Subject | Re: [PATCH 2/2] perf intel-pt: Fix corrupt data after perf inject from |
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On Wed, Aug 19, 2020 at 04:47:51PM +0800, Leo Yan wrote: > From: Al Grant <al.grant@arm.com> > > Commit 42bbabed09ce ("perf tools: Add hw_idx in struct branch_stack") > changed the format of branch stacks in perf samples. When samples use > this new format, a flag must be set in the corresponding event. > Synthesized branch stacks generated from Intel PT were using the new > format, but not setting the event attribute, leading to consumers > seeing corrupt data. This patch fixes the issue by setting the event > attribute to indicate use of the new format. > > Fixes: 42bbabed09ce ("perf tools: Add hw_idx in struct branch_stack") > Signed-off-by: Al Grant <al.grant@arm.com> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
Arnaldo, please consider.
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> --- > tools/perf/util/intel-pt.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c > index 2a8d245351e7..0af4e81c46e2 100644 > --- a/tools/perf/util/intel-pt.c > +++ b/tools/perf/util/intel-pt.c > @@ -3017,8 +3017,15 @@ static int intel_pt_synth_events(struct intel_pt *pt, > > if (pt->synth_opts.callchain) > attr.sample_type |= PERF_SAMPLE_CALLCHAIN; > - if (pt->synth_opts.last_branch) > + if (pt->synth_opts.last_branch) { > attr.sample_type |= PERF_SAMPLE_BRANCH_STACK; > + /* > + * We don't use the hardware index, but the sample generation > + * code uses the new format branch_stack with this field, > + * so the event attributes must indicate that it's present. > + */ > + attr.branch_sample_type |= PERF_SAMPLE_BRANCH_HW_INDEX; > + } > > if (pt->synth_opts.instructions) { > attr.config = PERF_COUNT_HW_INSTRUCTIONS; > -- > 2.17.1 >
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