Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932420AbVJGMaF (ORCPT ); Fri, 7 Oct 2005 08:30:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932504AbVJGMaF (ORCPT ); Fri, 7 Oct 2005 08:30:05 -0400 Received: from cantor.suse.de ([195.135.220.2]:52673 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S932420AbVJGMaC (ORCPT ); Fri, 7 Oct 2005 08:30:02 -0400 From: Andi Kleen To: "Vladimir B. Savkin" Subject: Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs Date: Fri, 7 Oct 2005 14:31:46 +0200 User-Agent: KMail/1.8 Cc: lkml , Andrew Morton , john stultz , discuss@x86-64.org References: <1127157404.3455.209.camel@cog.beaverton.ibm.com> <20051007122624.GA23606@tentacle.sectorb.msk.ru> In-Reply-To: <20051007122624.GA23606@tentacle.sectorb.msk.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200510071431.47245.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1785 Lines: 52 On Friday 07 October 2005 14:26, Vladimir B. Savkin wrote: > On Mon, Sep 19, 2005 at 12:16:43PM -0700, john stultz wrote: > > Andrew, > > This patch should resolve the issue seen in bugme bug #5105, where it > > is assumed that dualcore x86_64 systems have synced TSCs. This is not > > the case, and alternate timesources should be used instead. > > > > For more details, see: > > http://bugzilla.kernel.org/show_bug.cgi?id=5105 > > I too have a box that shows the symptoms from bugzilla entry above. > The system is Asus A8V Deluxe MB with > "AMD Athlon(tm) 64 X2 Dual Core Processor 3800+". > > The patch below did not fix the problem, while "idle=poll" did. > Hope this helps, dmesg attached. Are you running the latest BIOS? -Andi > > > Please consider for inclusion in your tree. > > > > thanks > > -john > > > > diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c > > --- a/arch/x86_64/kernel/time.c > > +++ b/arch/x86_64/kernel/time.c > > @@ -959,9 +959,6 @@ static __init int unsynchronized_tsc(voi > > are handled in the OEM check above. */ > > if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) > > return 0; > > - /* All in a single socket - should be synchronized */ > > - if (cpus_weight(cpu_core_map[0]) == num_online_cpus()) > > - return 0; > > #endif > > /* Assume multi socket systems are not synchronized */ > > return num_online_cpus() > 1; > > ~ > > :wq > > With best regards, > Vladimir Savkin. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/