From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini 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 Message-ID: <53DA6FBE.1020500@redhat.com> References: <1406800033-13404-1-git-send-email-imammedo@redhat.com> <1406800033-13404-2-git-send-email-imammedo@redhat.com> <20140731154747.GA7160@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 To: Borislav Petkov , Igor Mammedov Return-path: In-Reply-To: <20140731154747.GA7160@pd.tnic> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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