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From: "Pallipadi, Venkatesh" <>
To: "Steven Rostedt" <>, "Ingo Molnar" <>
Cc: "LKML" <>,
	"Linus Torvalds" <>,
	"Andrew Morton" <>,
	"Thomas Gleixner" <>,
	"Brown, Len" <>,
	"Adam Belay" <>,
	"Peter Zijlstra" <>,
	"Andi Kleen" <>
Subject: RE: [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait
Date: Thu, 10 Jan 2008 09:31:39 -0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>


>-----Original Message-----
>[] On Behalf Of Steven Rostedt
>Sent: Thursday, January 10, 2008 6:44 AM
>To: Ingo Molnar
>Cc: LKML; Linus Torvalds; Andrew Morton; Thomas Gleixner; 
>Brown, Len; Pallipadi, Venkatesh; Adam Belay; Peter Zijlstra; 
>Andi Kleen
>Subject: Re: [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait
>On Thu, 10 Jan 2008, Ingo Molnar wrote:
>> > FYI, I just hit this hang on 2.6.24-rc6 without any extra 
>patches. So,
>> > unless 2.6.24-rc7 did anything to fix this issue, this is a high
>> > priority bug (IMHO).
>> i'm wondering why this only triggered now. Is this something new in
>> 2.6.24?
>It only triggeres with the switching of the idle governors. 
>And not just
>one, you need to switch twice. The first loading of a governor does not
>call cpu_idle_wait, but the second one does. NO_HZ must also 
>be enabled,
>plus this needs to happen when no events or threads are 
>scheduled to run
>on a CPU, which limits this to boot up.
>Also, this only seems to happen on my 2x2 (4way) and only once 
>in a while.
>I'm surprised that I'm the only one so far to report it. I can 
>boot up the
>2.6.23 kernel on this box to see if it also hangs sometimes. But, as I
>said, it may take several hundreds of tries to see it.

With 2.6.23, you can try compiling acpi processor.ko as a module and
doing insmod and rmmod in a loop. That should call cpu_idle_wait very


  reply	other threads:[~2008-01-10 17:52 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-08  2:27 [RFC PATCH] kick sleeping idle CPUS on cpu_idle_wait Steven Rostedt
2008-01-08  3:33 ` Andi Kleen
2008-01-09 20:42   ` [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait Steven Rostedt
2008-01-09 22:12     ` Steven Rostedt
2008-01-10 13:45       ` Ingo Molnar
2008-01-10 14:43         ` Steven Rostedt
2008-01-10 17:31           ` Pallipadi, Venkatesh [this message]
2008-01-10 18:03             ` Steven Rostedt
2008-01-09 23:42     ` Andrew Morton
2008-01-10  0:05       ` Steven Rostedt
2008-01-10  0:12     ` Pallipadi, Venkatesh
     [not found]     ` <>
2008-02-08  1:05       ` [PATCH] x86: Simplify cpu_idle_wait Venki Pallipadi
2008-02-08 10:28         ` Andi Kleen
2008-02-08 17:24           ` Venki Pallipadi
2008-02-08 18:45             ` Andi Kleen
2008-02-09  9:33             ` Thomas Gleixner
2008-04-10 16:49               ` Venki Pallipadi

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