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

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Message-ID: <alpine.LFD.2.00.1005261428030.2995@localhost.localdomain>
Date:	Wed, 26 May 2010 14:30:45 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Brian Bloniarz <bmb@...enacr.com>
cc:	"H. Peter Anvin" <hpa@...or.com>,
	Dan Magenheimer <dan.magenheimer@...cle.com>,
	john stultz <johnstul@...ibm.com>, Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	Andi Kleen <andi@...stfloor.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

On Tue, 25 May 2010, Brian Bloniarz wrote:

> On 05/24/2010 09:33 PM, Brian Bloniarz wrote:
> > So what's wrong with just adding a
> > /sys/devices/system/clocksource/clocksource0/tsc_khz?

It's wrong because TSC is an x86'ism.
 
> As an RFC:
> 
> Add clocksource.sys_register & sys_unregister so the
> current clocksource can add supplemental information to
> /sys/devices/system/clocksource/clocksource0/
> 
> Export tsc_khz when current_clocksource==tsc so that
> daemons like NTP can account for the variability of
> calibration results.

I'd rather see a generic solution which provides the information of
the current (and possibly those of the available) clock source(s). 

This x86 centric TSC world view is horrible.

Thanks,

	tglx
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