Re: [patch] genapic: optimize & fix APIC mode setup

[Andi Kleen <ak@suse.de>]

On Monday 13 November 2006 02:50, Siddha, Suresh B wrote:
> On Sat, Nov 11, 2006 at 04:20:24PM +0100, Andi Kleen wrote:
> > On Saturday 11 November 2006 16:14, Ingo Molnar wrote:
> > > 
> > >  - removed the CPU hotplug hacks, switching the default for small
> > >    systems back from phys-flat to logical-flat. The switching to logical 
> > >    flat mode on small systems fixed sporadic ethernet driver timeouts i 
> > >    was getting on a dual-core Athlon64 system:
> > 
> > That will break CPU hotplug on some Intel systems (Ashok can give details) 
> 
> There is an issue of using clustered mode along with cpu hotplug. More details
> are at the below link.

Thanks Suresh.

> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=113261865814107&w=2

I should add i have no definite proof this is an issue on AMD systems
too, but I changed it there too anyways to better be safe than sorry
(and there is not very much performance difference anyways)

Now if it causes device driver issues that's different of course. I wasn't
aware of this before.

-Andi