Re: [PATCH] x86_64: make amd quad core 8 socket system not be clustered_box v2

[Yinghai Lu]

On Tue, Feb 26, 2008 at 1:24 PM, Ravikiran Thirumalai <kiran@xxxxxxxxxxx> wrote:
>
> On Tue, Feb 26, 2008 at 01:10:57PM -0800, Yinghai Lu wrote:
>  >On Tue, Feb 26, 2008 at 12:32 PM, Ravikiran Thirumalai
>  ><kiran@xxxxxxxxxxx> wrote:
>  >> On Tue, Feb 26, 2008 at 11:00:58AM -0800, Yinghai Lu wrote:
>  >>  >
>  >>  >1. if acpi=off ?
>  >>
>  >>  Well that is not a realistic scenario for any multi chassi NUMA machine,
>  >>  since the proximity information is very important and turning acpi off
>  >>  deprives the OS of this information.
>  >
>  >actually OS should detect the distance instead of rely on SLIT.
>
>  How does it do that?  ACPI SRAT is needed to determine this, and it wouldn't
>  work if acpi=off.

srat only have apicid to node mapping, and ram to node mapping.

for amd64 system, when acpi=off
ram to node mapping can be retrieved from pci conf space
apicid to node mapping could be calculated too... with boot_cpu_id
...plus coreid bits.

YH
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