From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: How to generate a HW NMI Date: Fri, 1 Oct 2010 16:01:23 -0400 Message-ID: <20101001200123.GA17776@dumpdata.com> References: <20101001141523.GB28639@dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Roger Cruz Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Fri, Oct 01, 2010 at 02:33:20PM -0500, Roger Cruz wrote: > Great ideas Konrad. I have ordered these parts. It will probably take > a few days before they get here. > The goal of using the HW NMI is to rule out any incorrect SW settings of > the Performance Monitoring counters used in Xen to triggered the NMI. Right. > > Someone else mentioned that another possibility as to why an NMI may not > be triggered is that the system is stuck handling an SMI interrupt. I > haven't studied Xen code with respect to SMIs yet, but I assume that Xen > doesn't do much in that area right? I was under the impression that the > BIOS usually set this up and the OSs could not even modify the handlers > as they were in protected RAM. Ugh. That is true - we have no notion of when the SMIs run. Not that the SMIs are actually working 100% all the time. Another thought, and this might be a complete shoot in the dark. Look in the upstream (2.6.36-rc6) blacklist.c file. There is an entry for that specific ThinkPad which activates the ACPI _OSI, maybe that needs to be done?