From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Matthew Wilcox <matthew@wil.cx>
Subject: Re: [PATCH] Prevent users from disabling tickless
Date: Wed, 22 Dec 2010 01:38:07 +0100
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Cc: Thomas Gleixner <tglx@linutronix.de>,
        Arjan van de Ven <arjan@infradead.org>, linux-kernel@vger.kernel.org
References: <20101221233942.GL1263@parisc-linux.org> <201012220046.23759.rjw@sisk.pl> <20101222002407.GM1263@parisc-linux.org>
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On Wednesday, December 22, 2010, Matthew Wilcox wrote:
> On Wed, Dec 22, 2010 at 12:46:23AM +0100, Rafael J. Wysocki wrote:
> > On Wednesday, December 22, 2010, Matthew Wilcox wrote:
> > > 
> > > Disabling NO_HZ has a serious negative effect on performance -- an extra
> > > 70us per I/O.  Prevent users from deselecting it.
> > > 
> > > Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
> > 
> > OTOH, it causes some systems to not work at all still.  Sadly.
> 
> It doesn't stop people from specifying nohz=off on the kernel command line.

Which still doesn't work for some people AFAICT.

Thanks,
Rafael
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