Date: Sun, 25 Jan 2009 10:34:38 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Jon Masters <jcm@redhat.com>
cc: Lee Revell <rlrevell@joe-job.com>, linux-rt-users@vger.kernel.org,
       LKML <linux-kernel@vger.kernel.org>, williams <williams@redhat.com>,
       "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Subject: Re: [RT] [RFC] simple SMI detector
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On Sat, 24 Jan 2009, Jon Masters wrote:
> > The only reasonable thing you can do on a SMI plagued system is to
> > identify the device which makes use of SMIs. Legacy ISA devices and
> > USB are usually good candidates. If that does not help, don't use it
> > for real-time :)
> 
> Indeed. This is why I wrote an smi_detector that sits in kernel space
> and can be reasonably sure measured discrepancies are attributable to
> SMI behavior. We want to log and detect such things before RT systems
> are deployed, not have users actively trying to work around SMI overhead
> after the fact.

Agreed. A tool to detect SMI disturbance is a good thing. It just
needs to be documented that users should take the results and talk to
their board vendor. I know that off the shelf hardware will not be
fixed, but industrial grade hardware vendors usually have an interest
to get such problems resolved.

Thanks,

	tglx
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