[lkml]   [2004]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] Yielding processor resources during lock contention
On Sonntag, 12. September 2004 12:43, Anton Blanchard wrote:
> cpu_relax doesnt tell us why we are busy looping. In this particular
> case we want to pass to the hypervisor which virtual cpu we are waiting
> on so the hypervisor make better scheduling decisions.

Ah, interesting. I think s390 could do the same with the upcoming 5.1 release
of z/VM. However, we decided to ask for an implementation of a futex hypercall
instead, which lets us implement the linux spinlock as a hypervisor semaphore.

> Did you manage to see any improvement by yielding to the hypervisor
> in cpu_relax?
I'm not sure if this has been measured, maybe Martin or Eberhard knows more.

Arnd <><
[unhandled content-type:application/pgp-signature]
 \ /
  Last update: 2005-03-22 14:06    [W:0.074 / U:6.068 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site