From: Arnaldo Carvalho de Melo <acme@redhat.com>
To: Vince Weaver <vweaver1@eecs.utk.edu>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] perf wrong branches event on AMD
Date: Thu, 1 Jul 2010 16:54:40 -0300 [thread overview]
Message-ID: <20100701195439.GJ4078@ghostprotocols.net> (raw)
In-Reply-To: <alpine.DEB.2.00.1007011526010.23160@cl320.eecs.utk.edu>
Em Thu, Jul 01, 2010 at 03:30:16PM -0400, Vince Weaver escreveu:
> Hello
>
> while doing some performance counter validation tests on some assembly
> language programs I noticed that the "branches:u" count was very wrong on
> AMD machines.
>
> It looks like the wrong event was selected.
>
> This is why event selection needs to be in user-space... it could be fixed
> instantly there, but the way things are done now it will take months to
> years for this fix to filter down to those trying to use perf counters...
Well, you can use:
rNNN (see 'perf list --help' on how to encode it) [Raw hardware event descriptor]
In the meantime.
- Arnaldo
next prev parent reply other threads:[~2010-07-01 19:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-01 19:30 [PATCH] perf wrong branches event on AMD Vince Weaver
2010-07-01 19:54 ` Arnaldo Carvalho de Melo [this message]
2010-07-02 11:38 ` Peter Zijlstra
2010-07-02 13:56 ` Vince Weaver
2010-07-02 14:23 ` Peter Zijlstra
2010-07-02 19:52 ` Vince Weaver
2010-07-03 13:54 ` Ingo Molnar
2010-07-04 0:30 ` David Dillow
2010-07-04 9:11 ` Ingo Molnar
2010-07-03 13:58 ` [tip:perf/urgent] perf, x86: Fix incorrect branches event on AMD CPUs tip-bot for Vince Weaver
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