Em Thu, Jan 21, 2021 at 02:54:46PM +0200, Adrian Hunter escreveu:
> perf_evlist__set_sid_idx() updates perf_sample_id with the evlist map
> index, cpu number and tid. It is passed indexes to the evsel's cpu and
> thread maps, but references the evlist's maps instead. That results in
> using incorrect cpu numbers on heterogeneous systems. Fix by using evsel
> maps.
>
> The id index (PERF_RECORD_ID_INDEX) is used by AUX area tracing when in
> sampling mode. Having an incorrect cpu number causes the trace data to
> be attributed to the wrong cpu, and can result in decoder errors because
> the trace data is then associated with the wrong process.
Can you please provide a Fixes: tag so that the sta...@kernel.org guys
can apply where appropriate?
Thanks,
- Arnaldo
> Signed-off-by: Adrian Hunter <adrian.hun...@intel.com>
> ---
> tools/lib/perf/evlist.c | 17 ++++-------------
> 1 file changed, 4 insertions(+), 13 deletions(-)
>
> diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
> index cfcdbd7be066..37be8042889f 100644
> --- a/tools/lib/perf/evlist.c
> +++ b/tools/lib/perf/evlist.c
> @@ -367,21 +367,13 @@ static struct perf_mmap* perf_evlist__alloc_mmap(struct
> perf_evlist *evlist, boo
> return map;
> }
>
> -static void perf_evlist__set_sid_idx(struct perf_evlist *evlist,
> - struct perf_evsel *evsel, int idx, int cpu,
> - int thread)
> +static void set_sid_idx(struct perf_evsel *evsel, int idx, int cpu, int
> thread)
> {
> struct perf_sample_id *sid = SID(evsel, cpu, thread);
>
> sid->idx = idx;
> - if (evlist->cpus && cpu >= 0)
> - sid->cpu = evlist->cpus->map[cpu];
> - else
> - sid->cpu = -1;
> - if (!evsel->system_wide && evlist->threads && thread >= 0)
> - sid->tid = perf_thread_map__pid(evlist->threads, thread);
> - else
> - sid->tid = -1;
> + sid->cpu = perf_cpu_map__cpu(evsel->cpus, cpu);
> + sid->tid = perf_thread_map__pid(evsel->threads, thread);
> }
>
> static struct perf_mmap*
> @@ -500,8 +492,7 @@ mmap_per_evsel(struct perf_evlist *evlist, struct
> perf_evlist_mmap_ops *ops,
> if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
> fd) < 0)
> return -1;
> - perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
> - thread);
> + set_sid_idx(evsel, idx, cpu, thread);
> }
> }
>
> --
> 2.17.1
>
--
- Arnaldo
