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Date: Sun, 25 May 2008 22:21:51 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
cc: LKML <linux-kernel@vger.kernel.org>,
       linux-rt-users <linux-rt-users@vger.kernel.org>, akpm@osdl.org,
       Ingo Molnar <mingo@elte.hu>, Clark Williams <clark.williams@gmail.com>,
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       "Luis Claudio R. Goncalves" <lclaudio@uudg.org>,
       Gregory Haskins <ghaskins@novell.com>, Andi Kleen <ak@suse.de>,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] x86: enable preemption in delay
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On Sun, 25 May 2008, Steven Rostedt wrote:
> 
> On Sun, 25 May 2008, Thomas Gleixner wrote:
> >
> > +/*
> > + * 5 usec on a 1GHZ machine. Not necessarily correct, but not too long
> > + * either.
> 
> And what happens when we have 10GHz boxes that can do migration in 1us,
> and the delay that is asked for is 2us. We can return early.  I don't like
> to place assumptions of this kind that can hurt with future hardware
> enhancements.

Do the math. It's 500ns on a 10GHz machine then. So nothing to worry
about and future proof. 

Also when those 10GHZ machines arrive the synchronized TSC should have
finally become reality.

Thanks,

	tglx