Subject: Re: [RFC] Fast assurate clock readable from user space and NMI
	handler
From: Thomas Gleixner <tglx@linutronix.de>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Ingo Molnar <mingo@elte.hu>, Daniel Walker <dwalker@mvista.com>,
       mbligh@google.com, linux-kernel@vger.kernel.org, johnstul@us.ibm.com
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Date: Tue, 27 Feb 2007 09:48:41 +0100
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On Tue, 2007-02-27 at 02:38 -0500, Mathieu Desnoyers wrote:
> > > The pit clocksource could be dropped pretty easy with my clocksource 
> > > update patches, which I'm still working on but you could easily drop 
> > > clock sources that aren't atomic like the pit .. Also the pit is 
> > > generally undesirable, so it's not going to be missed.
> > 
> > that's totally unacceptable, and i'm amazed you are even suggesting it - 
> > often the PIT ends up being the most reliable hardware clock in a PC. 
> > Btw., what's wrong with the spinlock that is protecting PIT access? It 
> > expresses the non-atomic property of the PIT just fine.
> > 
> 
> I am concerned about the automatic fallback to the PIT when no other
> clock source is available. 

And what are you going to use then ? Just kill the box, when nothing
else than PIT is there ? 

	tglx


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