Nathan Lynch wrote:
> 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?
>
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
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