Re: [discuss] Weird cpu mapping on 8-way dual-core machine

From: Yinghai Lu
Date: Wed Feb 27 2008 - 01:22:06 EST


On Tue, Feb 26, 2008 at 9:48 PM, Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
> On Tue, Feb 26, 2008 at 9:58 AM, Francisco Jesús Martínez Serrano
> <franjesus@xxxxxxxxx> wrote:
> > 2008/2/26, Andre Przywara:
> >
> > > So your BIOS option disables the shifting workaround and everything
> > > works as intended by the specification, although I am not sure whether
> > > you have any side effects (see above).
> >
> > Maybe I'm getting some side effects, but I'm not sure, when running an
> > OpenMP code, I get a lot of numa_misses, at node1 and the same number
> > of numa_foreign at node0.
> >
> > Out of pure ignorance, I was wondering if it could be related to the
> > node0 getting 505896 pages (I believe that's 1976.2 MB) of
> > ZONE_DMA32. I've seen options to disable DMA and DMA32. Is it safe?
> >
> can you try x86.git#testing ?
>
> http://people.redhat.com/mingo/x86.git/README
>
> and connect with serial console.
>
> command line:
> apic=debug acpi.debug_level=0x0000000F debug console=uart8250,io,0x3f8,115200n8
>
core fix is in x86.git#testing
http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ae2627a87c6f186ced0539d8e6f7a2c78dabc4c5

it will make sure that apicid to node mapping is right.
esp don't have SRAT or wrong SRAT, and your system have apicid lifting

YH
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