Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs

[john stultz <johnstul@us.ibm.com>]

On Sat, 2005-10-08 at 14:11 +0400, Vladimir B. Savkin wrote:
> On Fri, Oct 07, 2005 at 02:31:46PM +0200, Andi Kleen wrote:
> > 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?
> 
> Just upgraded to the lastest BIOS (revision 1014), nothing changed.
> Only with "idle=poll" timers run normally.

>From your dmesg, it appears that there are no other timesources other
then the TSC available on your hardware. So I'm guessing idle=poll is
keeping the CPUs from halting the TSC and keeping them synched. 


I would think that the ACPI PM timer would be supported, but I don't see
anything about it in your dmesg. Could you make sure it is properly
configured in?

thanks
-john


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