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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: linuxppc-dev@lists.ozlabs.org, paulus@samba.org,
	Anton Blanchard <anton@samba.org>,
	acme@ghostprotocols.net, a.p.zijlstra@chello.nl
Subject: Re: [PATCH] powerpc: perf: Handle events that raise an exception without overflowing
Date: Thu, 17 Mar 2011 07:34:26 +1100	[thread overview]
Message-ID: <1300307666.22236.1179.camel@pasglop> (raw)
In-Reply-To: <20110316125053.GA7387@elte.hu>

On Wed, 2011-03-16 at 13:50 +0100, Ingo Molnar wrote:
> * Anton Blanchard <anton@samba.org> wrote:
> 
> > 
> > Events on POWER7 can roll back if a speculative event doesn't
> > eventually complete. Unfortunately in some rare cases they will
> > raise a performance monitor exception. We need to catch this to
> > ensure we reset the PMC. In all cases the PMC will be 256 or less
> > cycles from overflow.
> > 
> > Signed-off-by: Anton Blanchard <anton@samba.org>
> > Cc: stable@kernel.org
> > ---
> > 
> > I would prefer not to add the PVR check, but I think we want to limit
> > this workaround to POWER7. Would a cpu feature be preferable?
> 
> There was no objection from the PowerPC folks so i'll send this fix Linuswards, ok?

Ah yes.

Ack.

Cheers,
Ben.

      reply	other threads:[~2011-03-16 20:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-09  3:38 [PATCH] powerpc: perf: Handle events that raise an exception without overflowing Anton Blanchard
2011-03-16 12:50 ` Ingo Molnar
2011-03-16 20:34   ` Benjamin Herrenschmidt [this message]

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