lkml.org 
[lkml]   [2007]   [Jun]   [27]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateWed, 27 Jun 2007 09:30:25 -0700
From"Paul E. McKenney" <>
SubjectRe: [PATCH] Force rcutorture tasks to spread over CPUs
On Wed, Jun 27, 2007 at 08:30:55AM +0200, Ingo Molnar wrote:
> 
> * Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > On Tue, 12 Jun 2007 21:28:04 -0700
> > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> > 
> > > +	while (!startwriters)
> > > +		barrier();	/* Force scheduler to spread over CPUs. */
> > 
> > one wonders whether a cpu_relax() would be a bit nicer here.  That 
> > implicitly does a barrier().
> > 
> > This patch doesn't make much sense for non-SMP builds?
> 
> i think this patch should be unnecessary because we found the real SMP 
> balancing bug in the upstream scheduler causing this rcu problem, see:
> 
>  commit 92c4ca5c3a5e180e9762438db235f41d192cb955
>  Author: Christoph Lameter <clameter@sgi.com>
>  Date:   Sat Jun 23 17:16:33 2007 -0700
> 
>      sched: fix next_interval determination in idle_balance()

Ingo is correct -- applying the above patch caused the scheduler to
correctly balance the rcutorture tasks, so that my patch to rcutorture
is no longer needed.  Which is a very good thing!  ;-)

							Thanx, Paul
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-27 16:33    [from the cache]
©2003-2008