Re: [PATCH] Fake NUMA emulation for PowerPC

From: Nathan Lynch
Date: Fri Dec 07 2007 - 17:26:06 EST


Hi Balbir-

Balbir Singh wrote:
>
>
> Here's a dumb simple implementation of fake NUMA nodes for PowerPC. Fake
> NUMA nodes can be specified using the following command line option
>
> numa=fake=<node range>
>
> node range is of the format <range1>,<range2>,...<rangeN>
>
> Each of the rangeX parameters is passed using memparse(). I find the patch
> useful for fake NUMA emulation on my simple PowerPC machine. I've tested it
> on a non-numa box with the following arguments
>
> numa=fake=1G
> numa=fake=1G,2G
> name=fake=1G,512M,2G
> numa=fake=1500M,2800M mem=3500M
> numa=fake=1G mem=512M
> numa=fake=1G mem=1G

So this doesn't appear to allow one to assign cpus to fake nodes? Do
all cpus just get assigned to node 0 with numa=fake?

A different approach that occurs to me is to use kexec with a doctored
device tree (i.e. with the ibm,associativity properties modified to
reflect your desired topology). Perhaps a little bit obscure, but it
seems more flexible.

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