From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@elte.hu, eranian@google.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf, x86: Add workaround for MEM_*_RETIRED errata BV98
Date: Wed, 01 May 2013 02:56:32 -0700 [thread overview]
Message-ID: <m261z3uipb.fsf@firstfloor.org> (raw)
In-Reply-To: <20130501090718.GA28253@dyad.programming.kicks-ass.net> (Peter Zijlstra's message of "Wed, 1 May 2013 11:07:19 +0200")
Peter Zijlstra <peterz@infradead.org> writes:
>
> So you're saying that if two SMT siblings count the same MEM_*_RETIRED event
> (on the same counter?) events can get accounted to the wrong sibling?
It can happen regardless of what event is enabled on the other counter.
> And when the other sibling doesn't have (the same counter?) enabled we
> can loose events?
doesn't have any events enabled.
> This begs the question what happens when the sibling does have the (same?)
> counter enabled but counting an all together different event; do we then still
> 'loose' events from the one sibling and add then to the other counter?
Yes, that is what the patch fixes.
Of course only if you actually apply it, and not lose it as usual.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2013-05-01 9:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 18:45 [PATCH] perf, x86: Add workaround for MEM_*_RETIRED errata BV98 Andi Kleen
2013-05-01 9:07 ` Peter Zijlstra
2013-05-01 9:56 ` Andi Kleen [this message]
2013-05-01 10:10 ` Ingo Molnar
2013-05-01 11:12 ` Peter Zijlstra
2013-05-01 18:13 ` Stephane Eranian
2013-05-01 19:13 ` Andi Kleen
2013-05-01 19:21 ` Stephane Eranian
2013-05-02 7:32 ` Peter Zijlstra
2013-05-06 17:41 ` Stephane Eranian
2013-05-06 19:00 ` Peter Zijlstra
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