Re: [PATCH] Reduce vm_stat cacheline contention in__vm_enough_memory

[Christoph Lameter]

On Fri, 14 Oct 2011, Dimitri Sivanich wrote:

> Increasing the ZVC deltas (threshold value in calculate*threshold == 125)
> does -seem- to give a small speedup in this case (maybe as much as 50 MB/sec?).

Hmm... The question is how much do the VM paths used for the critical path
increment the vmstat counters on average per second? If we end up with
hundred of updates per second from each thread then we still have a
problem that can only be addressed by increasing the deltas beyond 125
meaning the fieldwidth must be increased to support 16 bit counters.

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