Re: [PATCH RT] convert RCU Preempt tasklet into softirq.

From: Paul E. McKenney
Date: Fri Jun 08 2007 - 11:00:30 EST


On Thu, Jun 07, 2007 at 09:16:51PM -0700, Paul E. McKenney wrote:
> On Thu, Jun 07, 2007 at 04:16:09PM -0400, Steven Rostedt wrote:
> > On Thu, 2007-06-07 at 14:51 -0400, Steven Rostedt wrote:
> >
> > > There might still be an issue here. With the patch I'm getting a really
> > > slow response time on networking. But that be because of other patches I
> > > have applied.
> >
> > I removed this patch and I can still get the network slowdown/hang. So
> > this patch is unrelated to this issue. RCU on the otherhand has not been
> > cleared of suspicion.
>
> Might the slowdown be due to different kernel threads running at different
> priorities? I could easily believe that changing the priority of the
> kernel thread processing RCU callbacks could have a noticeable effect
> on performance in some cases.
>
> In other news, passed a set of kernbenches at this end, so starting
> an rcutorture.

And rcutorture passed 8 hours on a 4-CPU Opteron box.

Thanx, Paul
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