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Date: Tue, 12 Oct 2010 18:56:23 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Andi Kleen <andi@firstfloor.org>
Subject: Re: [RFC] [PATCH] allow low HZ values?
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Cc: Marcio Saito <marcio@cyclades.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Jiri Slaby <jirislaby@gmail.com>, Peter Zijlstra <peterz@infradead.org>,
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	LKML <linux-kernel@vger.kernel.org>,
	Tim Pepper <lnxninja@linux.vnet.ibm.com>, jblunck@infradead.org,
	Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
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On Tue, 12 Oct 2010, Andi Kleen wrote:
> Thomas Gleixner <tglx@linutronix.de> writes:
> > We have told HPC folks for years that we need a kind of "NOHZ" mode
> > for HPC where we can transparently switch off the tick when only one
> > user space bound thread is active and switch back to normal once this
> > thing terminates or goes into the kernel via a syscall. Sigh, nothing
> > happened ever except for repeating the same crap patches over and
> > over.
> 
> Jan Blunck posted a patch for this exactly few months ago.
> Unfortunately it didn't get the accounting right, but other than
> that it seemed like a reasonable starting point.

Unfortunately it did not get a lot of other things right either.

Thanks,

	tglx