From: Ingo Molnar <mingo@elte.hu>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Lee Revell <rlrevell@joe-job.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@osdl.org>
Subject: Re: RCU latency regression in 2.6.16-rc1
Date: Tue, 24 Jan 2006 10:23:30 +0100 [thread overview]
Message-ID: <20060124092330.GA7060@elte.hu> (raw)
In-Reply-To: <20060124091730.GA31204@us.ibm.com>
* Paul E. McKenney <paulmck@us.ibm.com> wrote:
> > Have not tested yet but it appears that will reduce it substantially:
> >
> > $ grep "dst_destroy (dst_rcu_free)" /proc/latency_trace | wc -l
> > 3027
> >
> > This implies the latency would be reduced to ~4ms, still not great but
> > it will be overshadowed by rt_run_flush/rt_garbage_collect.
>
> The other patch to try would be Dipankar Sarma's patch at:
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=113657112726596&w=2
>
> This patch was primarily designed to reduce memory overhead, but given
> that it tends to reduce batch size, it should also reduce latency.
if this solves Lee's problem, i think we should apply this as a fix, and
get it into v2.6.16. The patch looks straightforward and correct to me.
Ingo
next prev parent reply other threads:[~2006-01-24 9:23 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
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 [this message]
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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