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Message-ID: <dcb0121f-611d-4104-80b9-941d535c5fd2@linux.intel.com>
Date: Wed, 3 Apr 2024 13:59:28 -0400
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Subject: Re: [PATCH v1] perf metrics: Remove the "No_group" metric group
To: Ian Rogers <irogers@google.com>, Peter Zijlstra <peterz@infradead.org>,
 Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>,
 Namhyung Kim <namhyung@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
 Jiri Olsa <jolsa@kernel.org>, Adrian Hunter <adrian.hunter@intel.com>,
 linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
 Andi Kleen <ak@linux.intel.com>
References: <20240403164636.3429091-1-irogers@google.com>
Content-Language: en-US
From: "Liang, Kan" <kan.liang@linux.intel.com>
In-Reply-To: <20240403164636.3429091-1-irogers@google.com>
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On 2024-04-03 12:46 p.m., Ian Rogers wrote:
> Rather than place metrics without a metric group in "No_group" place
> them in a a metric group that is their name. Still allow such metrics
> to be selected if "No_group" is passed, this change just impacts perf
> list.

So it looks like the "No_group" is not completely removed.
They are just not seen in the perf list, but users can still use it via
perf stat -M No_group, right?

If so, why we want to remove it from perf list? Where can the end user
know which metrics are included in the No_group?

If the No_group is useless, why not completely remove it?

Thanks,
Kan

> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/util/metricgroup.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 79ef6095ab28..6ec083af14a1 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -455,7 +455,7 @@ static int metricgroup__add_to_mep_groups(const struct pmu_metric *pm,
>  	const char *g;
>  	char *omg, *mg;
>  
> -	mg = strdup(pm->metric_group ?: "No_group");
> +	mg = strdup(pm->metric_group ?: pm->metric_name);
>  	if (!mg)
>  		return -ENOMEM;
>  	omg = mg;
> @@ -466,7 +466,7 @@ static int metricgroup__add_to_mep_groups(const struct pmu_metric *pm,
>  		if (strlen(g))
>  			me = mep_lookup(groups, g, pm->metric_name);
>  		else
> -			me = mep_lookup(groups, "No_group", pm->metric_name);
> +			me = mep_lookup(groups, pm->metric_name, pm->metric_name);
>  
>  		if (me) {
>  			me->metric_desc = pm->desc;