From: Ingo Molnar <mingo@elte.hu>
To: Lee Revell <rlrevell@joe-job.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@osdl.org>,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: RCU latency regression in 2.6.16-rc1
Date: Tue, 24 Jan 2006 09:11:18 +0100 [thread overview]
Message-ID: <20060124081118.GB25855@elte.hu> (raw)
In-Reply-To: <1138089833.2771.86.camel@mindpipe>
* Lee Revell <rlrevell@joe-job.com> wrote:
> On Tue, 2006-01-24 at 09:01 +0100, Ingo Molnar wrote:
> > * Lee Revell <rlrevell@joe-job.com> wrote:
> >
> > > On Tue, 2006-01-24 at 08:56 +0100, Ingo Molnar wrote:
> > > > * Lee Revell <rlrevell@joe-job.com> wrote:
> > > >
> > > > > I ported the latency tracer to 2.6.16 and got this 13ms latency within
> > > > > a few hours. This is a regression from 2.6.15.
> > > > >
> > > > > It appears that RCU can invoke ipv4_dst_destroy thousands of times in
> > > > > a single batch.
> > > >
> > > > could you try the PREEMPT_RCU patch below?
> > >
> > > Sure. If it works do you see this making it in 2.6.16? Otherwise we
> > > still would have a regression...
> >
> > nope, that likely wont make v2.6.16, which is frozen already.
> >
>
> Well, the last latency regression I found, I was told "I wish you'd
> caught this at 2.6.15-rc1, something could have been done". Now I've
> found another one at the -rc1 stage, and there's still nothing that
> can be done?
i did not say that - it should clearly be fixed for 2.6.16. But
nevertheless we should do PREEMPT_RCU in v2.6.17, because RCU related
latencies are hard to fix in general.
Ingo
next prev parent reply other threads:[~2006-01-24 8:10 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-24 7:52 RCU latency regression in 2.6.16-rc1 Lee Revell
2006-01-24 7:56 ` Ingo Molnar
2006-01-24 7:58 ` Lee Revell
2006-01-24 8:01 ` Ingo Molnar
2006-01-24 8:03 ` Lee Revell
2006-01-24 8:11 ` Ingo Molnar [this message]
2006-01-24 8:07 ` Lee Revell
2006-01-24 8:13 ` Ingo Molnar
2006-01-24 8:15 ` Lee Revell
2006-01-24 9:17 ` Paul E. McKenney
2006-01-24 9:23 ` Ingo Molnar
2006-01-24 9:44 ` Lee Revell
2006-01-24 16:28 ` Dipankar Sarma
2006-01-24 21:38 ` Dipankar Sarma
2006-01-25 21:28 ` Lee Revell
2006-01-25 22:56 ` Ingo Molnar
2006-01-25 23:13 ` Lee Revell
2006-01-26 19:18 ` Paul E. McKenney
2006-01-27 18:55 ` Lee Revell
2006-01-28 17:03 ` Dipankar Sarma
2006-01-28 18:00 ` Lee Revell
2006-01-28 18:51 ` Lee Revell
2006-01-28 19:34 ` Dipankar Sarma
2006-01-28 19:46 ` Lee Revell
2006-01-28 19:52 ` Eric Dumazet
2006-01-29 7:38 ` Lee Revell
2006-01-29 7:51 ` Ingo Molnar
2006-01-29 8:21 ` Lee Revell
2006-01-30 4:36 ` Paul E. McKenney
2006-01-30 4:55 ` Eric Dumazet
2006-01-30 5:11 ` Paul E. McKenney
2006-01-30 5:52 ` David S. Miller
2006-01-30 10:00 ` Paul E. McKenney
2006-02-12 0:45 ` Lee Revell
2006-01-24 16:57 ` Dipankar Sarma
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