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From: Ingo Molnar <mingo@elte.hu>
To: Mike Galbraith <efault@gmx.de>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	rjw@sisk.pl, a.p.zijlstra@chello.nl,
	linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org
Subject: Re: [Bug #12208] uml is very slow on 2.6.28 host
Date: Thu, 18 Dec 2008 15:37:52 +0100	[thread overview]
Message-ID: <20081218143752.GB10548@elte.hu> (raw)
In-Reply-To: <1229494628.5280.24.camel@marge.simson.net>


* Mike Galbraith <efault@gmx.de> wrote:

> On Tue, 2008-12-16 at 16:27 +0100, Miklos Szeredi wrote:
> 
> > Is there a way to trace what is happening in the scheduler?
> 
> Sure.  Ingo has a script for gathering info (attached), if you run it, 
> please gzip up the output and send me a copy offline to eyeball.
> 
> There's also ftrace, but I've not tried that yet, so can't offer any 
> advice, I use primitive but effective time_after() + printk() with klogd 
> wakeup disabled (deadlock).

btw., there's a recent commit:

  32a7600: printk: make printk more robust by not allowing recursion

since then printk shouldnt deadlock anymore, even if called from within 
the scheduler.

Btw., ftrace_printk() can be used similarly (and you can capture it 
nonstop via /debug/tracing/trace_pipe), and should not deadlock either.

	Ingo

  reply	other threads:[~2008-12-18 14:38 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-13 16:29 2.6.28-rc8-git1: Reported regressions from 2.6.27 Rafael J. Wysocki
2008-12-13 16:29 ` [Bug #11849] default IRQ affinity change in v2.6.27 (breaking several SMP PPC based systems) Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12061] snd_hda_intel: power_save: sound cracks on powerdown Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12047] ACPI toshiba: only register rfkill if bt is enabled Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12028] i915 DRM is broken in 2.6.28-rc4 Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12159] 2.6.28-rc6-git1 -- No sound produced from Intel HDA ALSA driver Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12160] networking oops after resume from s2ram (2.6.28-rc6) Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12156] v2.6.28-rc2: x86_32 relocation regression? Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12100] resume (S2R) broken by Intel microcode module, on A110L Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12155] Regression in 2.6.28-rc and 2.6.27-stable - hibernate related Rafael J. Wysocki
2008-12-13 18:45   ` Fabio Comolli
2008-12-13 18:56     ` Rafael J. Wysocki
2008-12-14 23:11       ` Dave Kleikamp
2008-12-16 19:07       ` Ingo Molnar
2008-12-16 19:14         ` Linus Torvalds
2008-12-16 19:18           ` Ingo Molnar
2008-12-16 19:51             ` Greg KH
2008-12-13 16:33 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2008-12-16  0:49   ` Miklos Szeredi
2008-12-16  3:25     ` Mike Galbraith
2008-12-16 10:26       ` Miklos Szeredi
2008-12-16 14:19         ` Mike Galbraith
2008-12-16 15:27           ` Miklos Szeredi
2008-12-17  6:17             ` Mike Galbraith
2008-12-18 14:37               ` Ingo Molnar [this message]
2008-12-16  6:56     ` Peter Zijlstra
2008-12-13 16:33 ` [Bug #12195] "dd" make kernel panic Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12178] Xorg crash at first start Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12209] oldish top core dumps (in its meminfo() function) Rafael J. Wysocki
2008-12-13 16:33 ` [Bug #12210] 2.6.28-rc8 big regression in VM Rafael J. Wysocki
2008-12-25 11:20   ` Wu Fengguang
2008-12-25 14:11     ` Rafael J. Wysocki
2009-02-26 18:06     ` Lukas Hejtmanek
2009-02-27  6:37       ` KOSAKI Motohiro
2009-03-03  2:16       ` Wu Fengguang
2009-03-03 14:13         ` Lukas Hejtmanek
2008-12-20 21:56 2.6.28-rc9-git1: Reported regressions from 2.6.27 Rafael J. Wysocki
2008-12-20 22:00 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
     [not found] <nn3SOLVZ28H.A.bY.CafaJB@chimera>
2009-01-11 11:41 ` Rafael J. Wysocki
2009-01-12 10:04   ` Miklos Szeredi
2009-01-12 12:28     ` Rafael J. Wysocki
2009-01-19 21:41 2.6.29-rc2-git1: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-01-19 21:45 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-01-26 11:35   ` Miklos Szeredi
2009-02-04 10:55 2.6.29-rc3-git6: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-02-04 10:58 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-02-05 18:41 greg
2009-02-14 20:48 2.6.29-rc5: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-02-14 20:50 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-02-22 13:58   ` Américo Wang
2009-02-23 14:27     ` Miklos Szeredi
2009-02-23 22:00 2.6.29-rc6: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-02-23 22:02 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-03-03 19:34 2.6.29-rc6-git7: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-03-03 19:41 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-03-14 19:11 2.6.29-rc8: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-03-14 19:20 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki
2009-03-21 17:01 2.6.29-rc8-git5: Reported regressions 2.6.27 -> 2.6.28 Rafael J. Wysocki
2009-03-21 17:07 ` [Bug #12208] uml is very slow on 2.6.28 host Rafael J. Wysocki

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