Re: 3.1-rc2: CONFIG_NUMA Question

[AmÃrico Wang]

On Thu, Aug 18, 2011 at 6:51 PM, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote:
> Hi,
>
> I have a SuperMicro X8DTH-6F motherboard with 2 cpus it has NUMA options in
> the BIOS; what parameters/should I be using for the NUMA options in the
> kernel?
>
> Â| |  Â[*] Numa Memory Allocation and Scheduler Support         | |
> Â| |  Â[ ] Old style AMD Opteron NUMA detection             | |
> Â| |  Â[*] ACPI NUMA detection                     Â| |
> Â| |  Â[ ] NUMA emulation                        | |
> Â| | Â Â(6) Maximum NUMA Nodes (as a power of 2) Â Â Â Â Â Â Â Â Â Â Â Â | |
>

That is Intel processor, right? If so, the things you selected here are enough,
the rest two is not what you need.

> Specifically, the maximum number of NUMA nodes? ÂWill this help to increase
> performance of large memory allocations/is there any downside
> to enabling this feature?

The max of NUMA nodes is specified by CONFIG_NODES_SHIFT,
in your case, it is 6, which means it supports up to 2^6 nodes.

If your hardware supports NUMA, yes, that certainly help to increase
the performance.

Thanks.
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