From: Jiri Olsa <jolsa@redhat.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>,
jolsa@kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 2/2] perf, tools, stat: Reset ids counter when retrying events
Date: Wed, 21 Feb 2018 15:37:23 +0100 [thread overview]
Message-ID: <20180221143723.GD2565@krava> (raw)
In-Reply-To: <20180221143337.GC24416@kernel.org>
On Wed, Feb 21, 2018 at 11:33:37AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Feb 21, 2018 at 03:31:17PM +0100, Jiri Olsa escreveu:
> > On Thu, Oct 05, 2017 at 07:00:29PM -0700, Andi Kleen wrote:
> > > From: Andi Kleen <ak@linux.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
>
> Yeah, I couldn't figure out the exact sequence, but I think that we need
> to reset those hash tables when doing a perf_evlist__close(), no? I.e.
> when we open we may get new ids, so need to rehash?
yes, I think we should reset it any time the event is closed
I'll check your changes
jirka
next prev parent reply other threads:[~2018-02-21 14:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-06 2:00 [PATCH 1/2] perf, tools, stat: Use xyarray dimensions to iterate fds Andi Kleen
2017-10-06 2:00 ` [PATCH 2/2] perf, tools, stat: Reset ids counter when retrying events Andi Kleen
2017-10-06 3:36 ` Andi Kleen
2018-02-21 14:00 ` Arnaldo Carvalho de Melo
2018-02-21 14:39 ` Jiri Olsa
2018-02-21 14:31 ` Jiri Olsa
2018-02-21 14:33 ` Arnaldo Carvalho de Melo
2018-02-21 14:37 ` Jiri Olsa [this message]
2018-02-21 14:33 ` [PATCH 1/2] perf, tools, stat: Use xyarray dimensions to iterate fds Jiri Olsa
2018-02-21 14:37 ` Arnaldo Carvalho de Melo
2018-03-06 6:41 ` [tip:perf/core] perf " tip-bot for Andi Kleen
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