diff mbox series

[1/2] perf script: Skip aggregation for stat events

Message ID 83d6c6c05c54bf00c5a9df32ac160718efca0c7a.1683280603.git.sandipan.das@amd.com
State New
Headers
Series [1/2] perf script: Skip aggregation for stat events |

Commit Message

Sandipan Das May 5, 2023, 10:02 a.m. UTC 
  The script command does not support aggregation modes by itself although
that can be achieved using post-processing scripts. Because of this, it
does not allocate memory for aggregated event values.

Upon running perf stat record, the aggregation mode is set in the perf
data file. If the mode is AGGR_GLOBAL, the aggregated event values are
accessed and this leads to a segmentation fault since these were never
allocated to begin with. Set the mode to AGGR_NONE explicitly to avoid
this.

E.g.

  $ perf stat record -e cycles true
  $ perf script

Before:
  Segmentation fault (core dumped)

After:
  CPU   THREAD             VAL             ENA             RUN            TIME EVENT
   -1   231919          162831          362069          362069          935289 cycles:u

Fixes: 8b76a3188b85 ("perf stat: Remove unused perf_counts.aggr field")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Cc: stable@vger.kernel.org # v6.2+
---
 tools/perf/builtin-script.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Namhyung Kim May 5, 2023, 11:43 p.m. UTC | #1 
Hello,

On Fri, May 5, 2023 at 3:03 AM Sandipan Das <sandipan.das@amd.com> wrote:
>
> The script command does not support aggregation modes by itself although
> that can be achieved using post-processing scripts. Because of this, it
> does not allocate memory for aggregated event values.
>
> Upon running perf stat record, the aggregation mode is set in the perf
> data file. If the mode is AGGR_GLOBAL, the aggregated event values are
> accessed and this leads to a segmentation fault since these were never
> allocated to begin with. Set the mode to AGGR_NONE explicitly to avoid
> this.
>
> E.g.
>
>   $ perf stat record -e cycles true
>   $ perf script
>
> Before:
>   Segmentation fault (core dumped)
>
> After:
>   CPU   THREAD             VAL             ENA             RUN            TIME EVENT
>    -1   231919          162831          362069          362069          935289 cycles:u
>
> Fixes: 8b76a3188b85 ("perf stat: Remove unused perf_counts.aggr field")
> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> Cc: stable@vger.kernel.org # v6.2+

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  tools/perf/builtin-script.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index 006f522d0e7f..c57be48d65bb 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -3647,6 +3647,13 @@ static int process_stat_config_event(struct perf_session *session __maybe_unused
>                                      union perf_event *event)
>  {
>         perf_event__read_stat_config(&stat_config, &event->stat_config);
> +
> +       /*
> +        * Aggregation modes are not used since post-processing scripts are
> +        * supposed to take care of such requirements
> +        */
> +       stat_config.aggr_mode = AGGR_NONE;
> +
>         return 0;
>  }
>
> --
> 2.34.1
>
Arnaldo Carvalho de Melo May 10, 2023, 5:37 p.m. UTC | #2 
Em Fri, May 05, 2023 at 04:43:20PM -0700, Namhyung Kim escreveu:
> Hello,
> 
> On Fri, May 5, 2023 at 3:03 AM Sandipan Das <sandipan.das@amd.com> wrote:
> >
> > The script command does not support aggregation modes by itself although
> > that can be achieved using post-processing scripts. Because of this, it
> > does not allocate memory for aggregated event values.
> >
> > Upon running perf stat record, the aggregation mode is set in the perf
> > data file. If the mode is AGGR_GLOBAL, the aggregated event values are
> > accessed and this leads to a segmentation fault since these were never
> > allocated to begin with. Set the mode to AGGR_NONE explicitly to avoid
> > this.
> >
> > E.g.
> >
> >   $ perf stat record -e cycles true
> >   $ perf script
> >
> > Before:
> >   Segmentation fault (core dumped)
> >
> > After:
> >   CPU   THREAD             VAL             ENA             RUN            TIME EVENT
> >    -1   231919          162831          362069          362069          935289 cycles:u
> >
> > Fixes: 8b76a3188b85 ("perf stat: Remove unused perf_counts.aggr field")
> > Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> > Cc: stable@vger.kernel.org # v6.2+
> 
> Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks, applied both to perf-tools, for v6.4.

- Arnaldo
diff mbox series

Patch

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 006f522d0e7f..c57be48d65bb 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -3647,6 +3647,13 @@  static int process_stat_config_event(struct perf_session *session __maybe_unused
 				     union perf_event *event)
 {
 	perf_event__read_stat_config(&stat_config, &event->stat_config);
+
+	/*
+	 * Aggregation modes are not used since post-processing scripts are
+	 * supposed to take care of such requirements
+	 */
+	stat_config.aggr_mode = AGGR_NONE;
+
 	return 0;
 }