WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Xen spinlock questions

>>> Jeremy Fitzhardinge <jeremy@xxxxxxxx> 11.08.08 20:10 >>>
>Jan Beulich wrote:
>> Running kernel builds on 8 vCPU-s competing for 4 pCPU-s shows a 10%
>> improvement in performance with the individual wakeup (patch attached
>> - probably sub-optimal, but I didn't seem to be able to think of a lock-less
>> mechanism to achieve the desired behavior), using ticket locks in the
>> kernel.
>
>What exactly are you measuring here?  Are you testing your 2.6.2x 
>forward-port with an adaptation of pv spinlocks using ticket locks as 
>the underlying locking mechanism?  Does the 10% improvement come 

Yes.

>compared to straightforward use of sched_poll, or compared to doing 
>spurious wakeup detection?

Compared to spurious wakeup detection done in the kernel, similar to
how you had done it in the latest version of your respective patch that
I have seen.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel