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

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Date:	Mon, 29 Feb 2016 11:10:35 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	acme@...nel.org, jolsa@...nel.org, eranian@...gle.com,
	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 1/6] perf, tools, stat: Check existence of
 frontend/backed stalled cycles

On Fri, Feb 26, 2016 at 04:27:56PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@...ux.intel.com>
> 
> 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@...ux.intel.com>

Acked-by: Jiri Olsa <jolsa@...nel.org>

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
>