Re: [patch v2 4/4] percpu_counter: use atomic64 for counter

From: Tejun Heo
Date: Wed Apr 13 2011 - 15:07:59 EST

On Wed, Apr 13, 2011 at 03:57:19PM +0800, wrote:
> This can improve some workloads with percpu_counter->lock heavily contented.
> For example, vm_committed_as sometimes causes the contention. We should tune
> the batch count, but if we can make percpu_counter better, why not? In a 24
> CPUs system, 24 processes run stress mmap()/mmunmap(), the atomic method
> gives 50x faster.

Christoph already raised the issue but I'd also love to know a bit
more detail on the test than "50x faster".


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