Re: Performance regression from switching lock to rw-sem foranon-vma tree

From: Davidlohr Bueso
Date: Mon Jun 17 2013 - 19:35:32 EST


On Tue, 2013-06-18 at 07:20 +0800, Alex Shi wrote:
> On 06/18/2013 12:22 AM, Davidlohr Bueso wrote:
> > After a lot of benchmarking, I finally got the ideal results for aim7,
> > so far: this patch + optimistic spinning with preemption disabled. Just
> > like optimistic spinning, this patch by itself makes little to no
> > difference, yet combined is where we actually outperform 3.10-rc5. In
> > addition, I noticed extra throughput when disabling preemption in
> > try_optimistic_spin().
> >
> > With i_mmap as a rwsem and these changes I could see performance
> > benefits for alltests (+14.5%), custom (+17%), disk (+11%), high_systime
> > (+5%), shared (+15%) and short (+4%), most of them after around 500
> > users, for fewer users, it made little to no difference.
>
> A pretty good number. what's the cpu number in your machine? :)

8-socket, 80 cores (ht off)


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