Re: [RFC][PATCH 14/26] sched, numa: Numa balancer

Rik van Riel
2012-07-14T16:22:02Z

On 07/13/2012 10:45 AM, Don Morris wrote:

>> IIRC the test consisted of a 16GB NUMA system with two 8GB nodes.
>> It was running 3 KVM guests, two guests of 3GB memory each, and
>> one guest of 6GB each.
>
> How many cpus per guest (host threads) and how many physical/logical
> cpus per node on the host? Any comparisons with a situation where
> the memory would fit within nodes but the scheduling load would
> be too high?

IIRC this particular test was constructed to have guests
A and B fit in one NUMA node, with guest C in the other
NUMA node.

With schednuma, guest A ended up on one NUMA node, guest
B on the other, and guest C was spread between both nodes.

Only migrating when there is plenty of free space available
means you can end up not doing the right thing when running
a few large workloads on the system.

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