Re: [PATCH] Fake NUMA emulation for PowerPC

Nathan Lynch wrote:

Hi Balbir-

Balbir Singh wrote:

quoted

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?

Yes, they all appear on node 0. We could have tweaks to distribute CPU's
as well.

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.

That would be interesting, but it always means that we need to run
kexec, which might involve two boots.

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL