linux-kernel - Re: [PATCH 0/9] perf/x86: implement HT counter corruption workaround

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Message-ID: <CABPqkBRKDBQFJ=nqggYJJrguU6iCyk6h5z1sO3_KNcZpgzbK2A@mail.gmail.com>
Date:	Thu, 5 Jun 2014 14:45:29 +0200
From:	Stephane Eranian <eranian@...gle.com>
To:	Andi Kleen <ak@...ux.intel.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"mingo@...e.hu" <mingo@...e.hu>, Jiri Olsa <jolsa@...hat.com>,
	"Yan, Zheng" <zheng.z.yan@...el.com>,
	Maria Dimakopoulou <maria.n.dimakopoulou@...il.com>
Subject: Re: [PATCH 0/9] perf/x86: implement HT counter corruption workaround

On Thu, Jun 5, 2014 at 12:28 AM, Andi Kleen <ak@...ux.intel.com> wrote:
>> There is no HW or FW workaround for this problem.
>
> Actually there is for global measurements:
>
> measure with Any bit set and divide by two.
>
> Please add a check that the any bit is set, and disable
> the workaround for that case.
>
I think this assume same event is measured on sibling counters at any time.
Otherwise, how does that eliminate the corruption?
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