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Date:   Fri, 24 Jul 2020 07:46:32 -0700
From:   Andi Kleen <ak@linux.intel.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     "Liang, Kan" <kan.liang@linux.intel.com>, acme@redhat.com,
        mingo@kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org,
        eranian@google.com, alexander.shishkin@linux.intel.com,
        like.xu@linux.intel.com
Subject: Re: [PATCH V7 07/14] perf/core: Add a new PERF_EV_CAP_COEXIST event
 capability
Message-ID: <20200724144632.GE1180481@tassilo.jf.intel.com>
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> Something that seems to 'work' is:
> '{cycles,cpu/instructions,period=50000/}', so maybe you can make the
> group modifier :S use any sampling event if there is one, and otherwise
> designate the leader.
> 
> Then you can write things like:
> 
>   '{slots, metric1, metric2, cpu/cycles,freq=50000/}:S'
> 
> and then since cycles is specified as a sampling event, it will use
> that.

Okay possible, but it makes things more complicated
for the user to understand and requires special documentation.
Hopefully it's worth it the internal simplification.

-andi