Re: [PATCH 1/2] x86: AMD: mark TSC unstable on APU family 15h models 10h-1fh

From: Paolo Bonzini
Date: Thu Jul 31 2014 - 12:33:34 EST


Il 31/07/2014 17:47, Borislav Petkov ha scritto:
> On Thu, Jul 31, 2014 at 09:47:12AM +0000, Igor Mammedov wrote:
>> Due to erratum #778 from
>> "Revision Guide for AMD Family 15h Models 10h-1Fh Processors,
>> Publication # 48931, Issue Date: May 2013, Revision: 3.10"
>>
>> TSC on affected processor, a core may drift under certain conditions,
>> which makes initially synchronized TSCs to become unsynchronized.
>
> Is this something you're seeing on a real system? If so, how do you
> trigger this?

http://thread.gmane.org/gmane.linux.kernel/1748516 says that Ingo's
time-warp-test fails miserably on this machine.

(The test is at
http://people.redhat.com/mingo/time-warp-test/time-warp-test.c)

Paolo
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