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Date: Thu, 5 Jun 2014 17:17:34 +0200
From: Borislav Petkov <bp@alien8.de>
To: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Stephane Eranian <eranian@google.com>,
        Matt Fleming <matt@console-pimps.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, "mingo@elte.hu" <mingo@elte.hu>,
        "ak@linux.intel.com" <ak@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>, "Yan, Zheng" <zheng.z.yan@intel.com>
Subject: Re: [PATCH 9/9] perf/x86: add syfs entry to disable HT bug workaround
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On Thu, Jun 05, 2014 at 05:45:24PM +0300, Maria Dimakopoulou wrote:
> The issue is that the outcoming leaked counts are not compensated
> by the incoming leaked counts of the sibling thread. With the workaround,
> corrupting events are always scheduled with an empty sibling counter.
> This means that their leaked counts are lost. So it is expected to see
> lower counts with the workaround. Note that this is not a side-effect of
> the workaround; leaked counts are expected to be lost with nothing
> measured on the sibling counter in general.
> 
> In a second series we intend to re-integrate the counts for counting mode
> events. The workaround makes this easier because it guarantees
> that the sibling counter is unused, thus its counts are purely leaked
> counts and they can be safely re-integrated.

IIUC, sounds to me like reintegrating the leaked counts from the unused
counter should be part of the workaround too, not a second series...

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--