lkml.org 
[lkml]   [2015]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH tip/core/rcu 19/19] rcu: Add fastpath bypassing funnel locking
On Thu, Jul 30, 2015 at 08:34:52AM -0700, Paul E. McKenney wrote:
> > If the extra read before the cmpxchg() does not hurt, we should do the
> > same for mutex and make the above redundant.
>
> I am pretty sure that different hardware wants it done differently. :-/
> So I agree that hard data would be good.
>
> I could probably further optimize the RCU code by checking for a
> single-node tree, but I am not convinced that this is worthwhile.
> However, skipping three cache misses in the uncontended case is
> definitely worthwhile, hence this patch. ;-)

I was mostly talking about the !mutex_is_locked() && mutex_try_lock()
thing. The fast path thing makes sense.


\
 
 \ /
  Last update: 2015-07-30 18:21    [W:0.153 / U:1.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site