Re: [PATCH] mm: introduce numa_zero_pfn

[JoonSoo Kim]

2012/12/13 Andi Kleen <andi@xxxxxxxxxxxxxx>:
>> I would expect a processor to fetch the zero page cachelines from the l3
>> cache from other sockets avoiding memory transactions altogether. The zero
>> page is likely in use somewhere so no typically no memory accesses should
>> occur in a system.
>
> It depends on how effectively the workload uses the caches. If something
> is a cache pig of the L3 cache, then even shareable cache lines may need
> to be refetched regularly.
>
> But if your workloads spends a significant part of its time reading
> from zero page read only data there is something wrong with the workload.
>
> I would do some data profiling first to really prove that is the case.

Okay.
I didn't know about L3 cache, before.
Now, I think that I need some data profiling!
Thanks for comment.
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