linux-kernel - Re: TSC unstable on Intel Pentium M processor 750

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Message-ID: <20090430093244.74fcb1af@torg>
Date:	Thu, 30 Apr 2009 09:32:44 -0500
From:	Clark Williams <williams@...hat.com>
To:	"Mao Yilu" <ylmao@...l.ustc.edu.cn>
Cc:	"'Henrique de Moraes Holschuh'" <hmh@....eng.br>,
	<linux-kernel@...r.kernel.org>
Subject: Re: TSC unstable on Intel Pentium M processor 750

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On Thu, 30 Apr 2009 15:40:02 +0800
"Mao Yilu" <ylmao@...l.ustc.edu.cn> wrote:

> > -----Original Message-----
> > From: linux-kernel-owner@...r.kernel.org
> > [mailto:linux-kernel-owner@...r.kernel.org] On Behalf Of Henrique de Moraes
> > Holschuh
> > Sent: Thursday, April 30, 2009 11:12 AM
> > To: Mao Yilu
> > Cc: 'Robert Hancock'; linux-kernel@...r.kernel.org
> > Subject: Re: TSC unstable on Intel Pentium M processor 750
> > 
> > On Thu, 30 Apr 2009, Mao Yilu wrote:
> > > But I still don't know why the TSC is not correct in the C1 state (hlt
> > > instruction). Is there anything more to influence the TSC? What happened
> > > when the CPU is not running under hlt instruction?
> > 
> > SMIs?  Laptops love that crap...
> 
> What is SMIs?
> 
>

System Management Interrupt. Usually handled by BIOS code and
completely invisible to Linux. 

Laptops and big servers (rackmount/blades) typically have tons of SMIs
going off to do thermal management, statisics and remote management.

Clark
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