Re: [PATCH] Fake NUMA emulation for PowerPC

From: David Rientjes
Date: Fri Dec 07 2007 - 23:46:09 EST


On Sat, 8 Dec 2007, Balbir Singh wrote:

> > You're going to want to distribute the cpu's based on how they match up
> > physically with the actual platform that you're running on. x86_64 does
>
> Could you explain this better, how does it match up CPU's with fake NUMA
> memory? Is there some smartness there? I'll try and look at the code and
> also see what I can do for PowerPC
>

numa_cpumask_lookup_table[] would return the correct cpumask for the fake
node index. Then all the code that uses node_to_cpumask() in generic
kernel code like the scheduler and VM still preserve their true NUMA
affinity that matches the underlying hardware. I tried to make x86_64
fake NUMA as close to the real thing as possible.

You also probably want to make all you changes dependent on
CONFIG_NUMA_EMU like the x86_64 case. That'll probably be helpful as you
extend this tool more and more.

David
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