linux-kernel - Re: [PATCH] x86: Export tsc related information in sysfs

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Message-ID: <20100524234221.GA5907@gargoyle.fritz.box>
Date:	Tue, 25 May 2010 01:42:21 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	john stultz <johnstul@...ibm.com>
Cc:	Dan Magenheimer <dan.magenheimer@...cle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Brian Bloniarz <bmb@...enacr.com>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Arjan van de Ven <arjan@...radead.org>,
	Venkatesh Pallipadi <venki@...gle.com>, chris.mason@...cle.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: Export tsc related information in sysfs

> > As more and more systems become dependent on clocksource==tsc
> > and more and more people assume nanosecond-class measurements
> > are relatively accurate, I'd expect the accuracy of tsc_khz
> > to become more important.  While desktop users might bristle
> > at an extra second of boot delay, I'll bet many server
> > farm administrators would gladly pay that upfront cost
> > if they know an option exists.
> 
> Maybe something like a tsc_long_calibration=1 option would allow for
> this?  

On a system with synchronized TSC and multiple cores you could also simply do 
a longer calibration on another core in the background after a quick "fast
calibration"

-Andi
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