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From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vweaver1@eecs.utk.edu>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
	Paul Mackerras <paulus@samba.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: Re: [PATCH] perf wrong branches event on AMD
Date: Fri, 02 Jul 2010 13:38:47 +0200	[thread overview]
Message-ID: <1278070727.1917.253.camel@laptop> (raw)
In-Reply-To: <alpine.DEB.2.00.1007011526010.23160@cl320.eecs.utk.edu>

On Thu, 2010-07-01 at 15:30 -0400, Vince Weaver wrote:
> 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...

Last time I checked apt-get upgrade/yum upgrade simply upgraded
everything, including kernels.. (and upgrades to userspace packages can
take months too)

Someone needs to build a new package and publish it, upgrading the
kernel is no harder than upgrading any other.

If you don't want to reboot, there's the -r option Arnaldo already
mentioned. There's also the option of writing a kernel module to poke at
the data table if you really really want to update a running kernel.

If you think this is a really "important" feature you could even make a
patch that exposes all these data tables to userspace through sysfs or
whatever and see if people think its worth the effort.

Personally I don't think people will ever use such a sysfs interface,
but hey, that's my opinion.

  parent reply	other threads:[~2010-07-02 11:39 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
2010-07-02 11:38 ` Peter Zijlstra [this message]
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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