linux-kernel - Re: [PATCH] Fix TSC calibration issues

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Message-ID: <alpine.LFD.1.10.0809031103090.3243@apollo.tec.linutronix.de>
Date:	Wed, 3 Sep 2008 11:11:34 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
cc:	Larry Finger <Larry.Finger@...inger.net>,
	LKML <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Alok Kataria <akataria@...are.com>,
	Michael Buesch <mb@...sch.de>
Subject: Re: [PATCH] Fix TSC calibration issues

On Tue, 2 Sep 2008, Linus Torvalds wrote:
> This is "wrongish".
> 
> You really should do the
> 
> 	tsc1 = tsc_read_refs(&pm1, hpet ? &hpet1 : NULL);   
> 	...
> 	tsc2 = tsc_read_refs(&pm2, hpet ? &hpet2 : NULL);
> 
> around the whole loop, because they get more exact with more time inside, 
> and they don't improve from looping around.

True. Just kept them at the place where my debug patches had left them.
 
> Also, that code is already _too_ unreadable. How about starting by just 
> moving the PIT calibration into a function of its own, like the appended 
> patch. And then as a separate patch, improving the heuristics for just the 
> PIT calibration.

Yeah, should have done that. But I was too tired to touch anything in
the code more complex than adding a few comments.
 
Thanks,

	tglx
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