linux-kernel - Re: [PATCH 2/2] perf, tools, stat: Reset ids counter when retrying events

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Date:   Wed, 21 Feb 2018 15:31:17 +0100
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 2/2] perf, tools, stat: Reset ids counter when retrying
 events

On Thu, Oct 05, 2017 at 07:00:29PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@...ux.intel.com>

ouch, sry for overlooking this

> 
> perf stat can retry opening events. After opening an file descriptor
> it adds the ids to the ecsel. Each event keeps a running
> count of ids. When we decide to close an evsel and retry
> with a different configuration this count needs to be reset,
> otherwise it can overflow the buffer.

how can this happen? we call store_counter_ids at the
end of the loop, when the evsel is all done and can't
be reconfigured

thanks,
jirka