From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759701AbYDNNlS (ORCPT ); Mon, 14 Apr 2008 09:41:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752541AbYDNNlA (ORCPT ); Mon, 14 Apr 2008 09:41:00 -0400 Received: from web52505.mail.re2.yahoo.com ([206.190.48.188]:33636 "HELO web52505.mail.re2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1759357AbYDNNk7 (ORCPT ); Mon, 14 Apr 2008 09:40:59 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=F4zdRq2NN0zwC5upXHDSQdlqVtS+i6f0poR8saSYRKuDDFAjhw9aIThPHmQZk8mAPJqtceP2KNOL4unqK4bUmsWSGFi8BKQPUEFg5tsMT76FnHIBCMgQEIkTrcCpOCyi0r51HfgkgRRbIAL2U3TZM+lWilOhZAWlirX/vyq94L8=; X-YMail-OSG: 32nL9gwVM1lFPZ1vFOWptsn_5Hi8dvFtukP2ZgPFYV2lJhmygwfgo.Rp9GnCYV7W0ojRqhCfIBBRygqMzRoDSAFR.eoAe11LOBfCSdxo4vGl7u6S3kVPV.n7u0cpE9W_kKwDWaJN7ucn0Hxl4oke7K3gMQ-- Date: Mon, 14 Apr 2008 06:40:57 -0700 (PDT) From: Marc Perkel Subject: Re: AMD Quad Core clock problem? To: Chris Snook Cc: linux-kernel@vger.kernel.org In-Reply-To: <47FFD3F3.50107@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Message-ID: <533265.33722.qm@web52505.mail.re2.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --- Chris Snook wrote: > Marc Perkel wrote: > > --- Chris Snook wrote: > > > >> Marc Perkel wrote: > >>> I was just wondering if there were any known > >> issues > >>> with AMD quad core phenom clock drift problems? > >> I';m > >>> running a 2.6.24 kernel and it's losing time. I > >>> remember the first dual core AMD chips had a lot > >> of > >>> clock issues. > >>> > >>> If this is something new let me know what > >> information > >>> to check and post to this list. > >> When reporting clock problems, please post dmesg. > > >> This has all the > >> interesting timekeeping-related log messages from > >> the kernel. Please > >> also describe the drift quantitatively. > >> > >> -- Chris > >> > > > > OK - thanks Chris. > > > > The drift is small. It loses a few seconds every > hour. > > And it might not be kernel related. I just > remembered > > the early dual core days when this took months to > get > > right. I'm running several dual core computers and > the > > only one drifting is the quad. All are running the > > same OS and kernel. > > With the older chips, each core had its own TSC, > which caused > synchronization problems. The Barcelona generation > chips (including > your Phenom) have a constant frequency TSC on the > northbridge, so they > should be immune to these problems. > > If it's steadily losing a few seconds every hour, > it's probably just > slightly mis-calibrated hardware. ntp should fix > this right up. If the > drift is more extreme than ntp can correct for, or > the drift keeps > changing, or time is jumping around, that is > definitely something that > could be a bug. > > > hpet clockevent registered > > TSC calibrated against HPET > > Marking TSC unstable due to TSCs unsynchronized > > It's possible that in future kernels we'll be a few > clock cycles more > accurate in calibrating this on Barcelona chips, but > calibration is only > as good as the standard of comparison. There will > always be hardware > that's slightly off, so run ntp, or use a nightly > ntpdate cronjob. If > your time starts drifting drastically or jumping > around, please yell > really loud. > > -- Chris > The chip I'm talking about is the Phenom chip. It's the AMD 9600 and the MB is an ASUS M3A78-EMH. Been toying with NTPD all weekend and the drift is such that it's just barely out of the range of NTP to correct it. Sometime if I sync the clock on startup it will work for a while but always falls back to the internal clock. I'm estimating it's losing 3-4 minutes a day. I also verified that I have the latest bios. It is possible that I have bad hardware but I doubt it. I think I might go ahead and start a bug report on this and see if this is just me or if anyone else is having these kind of problems as well. Just wanted to get a little feedback first to make sure I'm not doing something stupid. Marc Perkel Junk Email Filter dot com http://www.junkemailfilter.com ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ