From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Leo Yan <leo.yan@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Al Grant <al.grant@arm.com>
Subject: Re: [PATCH 1/2] perf cs-etm: Fix corrupt data after perf inject from
Date: Thu, 27 Aug 2020 14:53:54 -0600 [thread overview]
Message-ID: <20200827205354.GE22307@xps15> (raw)
In-Reply-To: <20200819084751.17686-1-leo.yan@linaro.org>
Hi Leo and Al,
On Wed, Aug 19, 2020 at 04:47:50PM +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 CoreSight ETM trace 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>
> Reviewed-by: Andrea Brunato <andrea.brunato@arm.com>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
> tools/perf/util/cs-etm.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index c283223fb31f..a2a369e2fbb6 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -1344,8 +1344,15 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
> attr.sample_type &= ~(u64)PERF_SAMPLE_ADDR;
> }
>
> - if (etm->synth_opts.last_branch)
> + if (etm->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;
> + }
I've see this patch before... I thought it had been merged - what happened?
Thanks,
Mathieu
>
> if (etm->synth_opts.instructions) {
> attr.config = PERF_COUNT_HW_INSTRUCTIONS;
> --
> 2.17.1
>
next prev parent reply other threads:[~2020-08-27 20:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 8:47 [PATCH 1/2] perf cs-etm: Fix corrupt data after perf inject from Leo Yan
2020-08-19 8:47 ` [PATCH 2/2] perf intel-pt: " Leo Yan
2020-08-24 12:41 ` Adrian Hunter
2020-08-31 20:38 ` Mathieu Poirier
2020-09-01 14:53 ` Arnaldo Carvalho de Melo
2020-08-27 20:53 ` Mathieu Poirier [this message]
2020-08-31 0:04 ` [PATCH 1/2] perf cs-etm: " Leo Yan
2020-09-01 14:54 ` Arnaldo Carvalho de Melo
2020-09-02 0:39 ` Leo Yan
2020-09-02 1:47 ` Arnaldo Carvalho de Melo
2020-09-02 2:12 ` Leo Yan
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