From: Ingo Molnar <mingo@elte.hu>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Matt Mackall <mpm@selenic.com>,
akpm@linux-foundation.org, Linux-kernel@vger.kernel.org
Subject: Re: Interesting interaction between lguest and CFS
Date: Tue, 5 Jun 2007 09:10:11 +0200 [thread overview]
Message-ID: <20070605071011.GA25163@elte.hu> (raw)
In-Reply-To: <1181002734.25878.56.camel@localhost.localdomain>
* Rusty Russell <rusty@rustcorp.com.au> wrote:
> This sounds like the waker process (nice 19) not getting a chance to
> run. You can hack around it for the moment by changing "nice(19)" in
> Documentation/lguest/lguest.c to something less aggressive.
even if the waker runs at nice+19, under CFS (which schedules
deterministically) it should not be delayed by a single nice-0 task by
more than ~70 msecs. That is a far cry from the 'seconds' that Matt saw
- and the sched stats he sent look anomalous too. Also, i'm not able to
reproduce it at all - while any nice+19 related problem should be
readily reproducable on my box too. So my current take is that this is
some sort of host-side CFS related problem and that the lguest host
threads somehow were the first ones that managed to trigger it in some
really bad way.
OTOH i do agree with your patch, that nice+19 thing is quite hacky :-)
Ingo
next prev parent reply other threads:[~2007-06-05 7:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-04 17:37 Interesting interaction between lguest and CFS Matt Mackall
2007-06-04 17:54 ` Ingo Molnar
2007-06-04 18:41 ` Matt Mackall
2007-06-05 7:19 ` Ingo Molnar
2007-06-05 14:03 ` Matt Mackall
2007-06-05 15:14 ` Dmitry Adamushko
2007-06-05 15:41 ` Dmitry Adamushko
2007-06-05 19:50 ` Ingo Molnar
2007-06-06 20:23 ` Matt Mackall
2007-06-08 9:34 ` Ingo Molnar
2007-06-08 10:18 ` Ingo Molnar
2007-06-04 18:11 ` Ingo Molnar
2007-06-04 18:42 ` Matt Mackall
2007-06-04 19:12 ` Ingo Molnar
2007-06-04 19:27 ` Matt Mackall
2007-06-04 19:40 ` Ingo Molnar
2007-06-04 19:59 ` Matt Mackall
2007-06-04 20:13 ` Ingo Molnar
2007-06-04 20:20 ` Ingo Molnar
2007-06-04 20:15 ` James Morris
2007-06-04 20:24 ` Ingo Molnar
2007-06-04 22:58 ` Olof Johansson
2007-06-05 1:02 ` Rusty Russell
2007-06-05 1:24 ` Stephen Rothwell
2007-06-05 2:23 ` Olof Johansson
2007-06-05 0:18 ` Rusty Russell
2007-06-05 2:31 ` Rusty Russell
2007-06-05 4:18 ` Matt Mackall
2007-06-05 4:37 ` Rusty Russell
2007-06-05 13:49 ` Matt Mackall
2007-06-05 19:38 ` Ingo Molnar
2007-06-05 10:43 ` Ingo Molnar
2007-06-05 19:08 ` Ingo Molnar
2007-06-06 20:19 ` Matt Mackall
2007-06-05 2:34 ` Matt Mackall
2007-06-05 7:10 ` Ingo Molnar [this message]
2007-06-05 9:23 ` Ingo Molnar
2007-06-05 14:06 ` Matt Mackall
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