Re: [PATCH v2] locking/pvqspinlock: Relax cmpxchg's to improve performance on some archs

[Peter Zijlstra]

On Tue, Jan 03, 2017 at 05:07:54PM -0500, Waiman Long wrote:
> On 01/03/2017 11:18 AM, Peter Zijlstra wrote:
> > On Sun, Dec 25, 2016 at 03:26:01PM -0500, Waiman Long wrote:
> >> A number of cmpxchg calls in qspinlock_paravirt.h were replaced by more
> >> relaxed versions to improve performance on architectures that use LL/SC.
> > Claim without numbers ;-)
> 
> Well it is hard to produce actual numbers here as I don't have the setup
> to gather data.

Surely RHT has big PPC machines around? I know that getting to them is a
wee bit of a bother, but they should be available somewhere.