linux-kernel - Re: [RFC patch 0/4] TSC calibration improvements

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Message-ID: <alpine.LFD.1.10.0809040920000.3381@nehalem.linux-foundation.org>
Date:	Thu, 4 Sep 2008 09:21:42 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Ingo Molnar <mingo@...e.hu>
cc:	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	Alok Kataria <akataria@...are.com>,
	Arjan van de Veen <arjan@...radead.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [RFC patch 0/4] TSC calibration improvements



On Thu, 4 Sep 2008, Ingo Molnar wrote:
> 
> ah - perhaps a dynamic statistical approach with an estimation of 
> worst-case calibration error (~= standard deviation) and a quality 
> threshold to reach? That could dramatically increase the number of 
> samples while also making it much faster in practice. Nifty!

Oh, no, I'm _much_ more nifty than that!

Instead of being very clever, I have a very _stupid_ algorithm, one that 
has very hardcoded expectations of exactly what it will see. And if it 
doesn't see exactly that, it just fails early. 

I'd post the patch, but I really need to actually _test_ it first, and I 
haven't rebooted yet.

		Linus
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