linux-kernel - Re: [PATCH v2 05/19] perf, tools: Support weak groups

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Date:   Tue, 22 Aug 2017 10:34:15 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Andi Kleen <andi@...stfloor.org>
Cc:     acme@...nel.org, jolsa@...nel.org, linux-kernel@...r.kernel.org,
        Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH v2 05/19] perf, tools: Support weak groups

On Fri, Aug 11, 2017 at 04:26:20PM -0700, Andi Kleen wrote:

SNIP

> diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
> index f709de54707b..d432965d728d 100644
> --- a/tools/perf/Documentation/perf-list.txt
> +++ b/tools/perf/Documentation/perf-list.txt
> @@ -47,6 +47,7 @@ counted. The following modifiers exist:
>   P - use maximum detected precise level
>   S - read sample value (PERF_SAMPLE_READ)
>   D - pin the event to the PMU
> + W - group is weak and will fallback to non-group if not schedulable
>  
>  The 'p' modifier can be used for specifying how precise the instruction
>  address should be. The 'p' modifier can be specified multiple times:
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 866da7aa54bf..ac605caf1a01 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -582,6 +582,32 @@ static bool perf_evsel__should_store_id(struct perf_evsel *counter)
>  	return STAT_RECORD || counter->attr.read_format & PERF_FORMAT_ID;
>  }
>  
> +static struct perf_evsel *reset_weak_group(struct perf_evsel *counter)
> +{
> +	struct perf_evsel *c2, *leader;
> +	bool is_open = true;
> +
> +	leader = counter->leader;
> +	pr_debug("Weak group for %s/%d failed\n",
> +			leader->name, counter->nr_members);

I'm getting 'branches/0' in here for you example:

[root@...va perf]# ./perf stat -v -e '{branches,branch-misses,l1d.replacement,l2_lines_in.all,l2_rqsts.all_code_rd}:W' -a sleep 1
Using CPUID GenuineIntel-6-3D
l1d.replacement -> cpu/umask=0x1,period=2000003,event=0x51/
l2_lines_in.all -> cpu/umask=0x7,period=100003,event=0xf1/
l2_rqsts.all_code_rd -> cpu/umask=0xe4,period=200003,event=0x24/
Weak group for branches/0 failed

I'd expect nr_members == 5 ... any idea?

thanks,
jirka