lkml.org 
[lkml]   [2013]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Performance regression from switching lock to rw-sem for anon-vma tree
From
Date
On Fri, 2013-06-14 at 15:47 -0700, Michel Lespinasse wrote:
> On Fri, Jun 14, 2013 at 3:31 PM, Davidlohr Bueso <davidlohr.bueso@hp.com> wrote:
> > A few ideas that come to mind are avoiding taking the ->wait_lock and
> > avoid dealing with waiters when doing the optimistic spinning (just like
> > mutexes do).
> >
> > I agree that we should first deal with the optimistic spinning before
> > adding the MCS complexity.
>
> Maybe it would be worth disabling the MCS patch in mutex and comparing
> that to the rwsem patches ? Just to make sure the rwsem performance
> delta isn't related to that.
>

I've tried to back out the MCS patch. In fact, for exim, it is about 1%
faster without MCS. So the better performance of mutex I saw was not
due to MCS. Thanks for the suggestion.

Tim



\
 
 \ /
  Last update: 2013-06-18 01:01    [W:0.564 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site