Re: [PATCH 1/6] perf, tools, stat: Check existence of frontend/backed stalled cycles

From: Jiri Olsa
Date: Mon Feb 29 2016 - 05:10:45 EST


On Fri, Feb 26, 2016 at 04:27:56PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> Only put the frontend/backend stalled cycles into the default
> perf stat events when the CPU actually supports them.
>
> This avoids empty columns with --metric-only on newer Intel CPUs.
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>

thanks,
jirka

> ---
> tools/perf/builtin-stat.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 8c0bc0f..24f222d 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -1441,7 +1441,7 @@ static int perf_stat_init_aggr_mode_file(struct perf_stat *st)
> */
> static int add_default_attributes(void)
> {
> - struct perf_event_attr default_attrs[] = {
> + struct perf_event_attr default_attrs0[] = {
>
> { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK },
> { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES },
> @@ -1449,8 +1449,14 @@ static int add_default_attributes(void)
> { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS },
>
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES },
> +};
> + struct perf_event_attr frontend_attrs[] = {
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_STALLED_CYCLES_FRONTEND },
> +};
> + struct perf_event_attr backend_attrs[] = {
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_STALLED_CYCLES_BACKEND },
> +};
> + struct perf_event_attr default_attrs1[] = {
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS },
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
> { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES },
> @@ -1567,7 +1573,19 @@ static int add_default_attributes(void)
> }
>
> if (!evsel_list->nr_entries) {
> - if (perf_evlist__add_default_attrs(evsel_list, default_attrs) < 0)
> + if (perf_evlist__add_default_attrs(evsel_list, default_attrs0) < 0)
> + return -1;
> + if (pmu_have_event("cpu", "stalled-cycles-frontend")) {
> + if (perf_evlist__add_default_attrs(evsel_list,
> + frontend_attrs) < 0)
> + return -1;
> + }
> + if (pmu_have_event("cpu", "stalled-cycles-backend")) {
> + if (perf_evlist__add_default_attrs(evsel_list,
> + backend_attrs) < 0)
> + return -1;
> + }
> + if (perf_evlist__add_default_attrs(evsel_list, default_attrs1) < 0)
> return -1;
> }
>
> --
> 2.5.0
>