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From: Paolo Bonzini <pbonzini@redhat.com>
To: Borislav Petkov <bp@alien8.de>, Igor Mammedov <imammedo@redhat.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
	mingo@redhat.com, tglx@linutronix.de, kvm@vger.kernel.org,
	mtosatti@redhat.com
Subject: Re: [PATCH 1/2] x86: AMD: mark TSC unstable on APU family 15h models 10h-1fh
Date: Thu, 31 Jul 2014 18:33:02 +0200	[thread overview]
Message-ID: <53DA6FBE.1020500@redhat.com> (raw)
In-Reply-To: <20140731154747.GA7160@pd.tnic>

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

  reply	other threads:[~2014-07-31 16:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-31  9:47 [PATCH 0/2] Avoid using TSC clocksource on AMD APUs affected by erratum 778 Igor Mammedov
2014-07-31  9:47 ` [PATCH 1/2] x86: AMD: mark TSC unstable on APU family 15h models 10h-1fh Igor Mammedov
2014-07-31 15:47   ` Borislav Petkov
2014-07-31 16:33     ` Paolo Bonzini [this message]
2014-08-01  9:02   ` Borislav Petkov
2014-07-31  9:47 ` [PATCH 2/2] x86: kvm: do not advertise stable clocksource if CPU has TSC drift BUG Igor Mammedov
2014-07-31 14:38   ` Paolo Bonzini

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