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

[Waiman Long]

On 01/04/2017 04:41 AM, Peter Zijlstra wrote:
> 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.

Yes, RHT does have PPC machines around. It is just I don't have
experience dealing with those machines yet. I will try to run some test
and include the numbers in the next version of the patch.

Cheers,
Longman