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RE: [Xen-devel] RE: [Patch] Fix IDLE issue with sedf scheduler on IA64

To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>, "Hollis Blanchard" <hollisb@xxxxxxxxxx>
Subject: RE: [Xen-devel] RE: [Patch] Fix IDLE issue with sedf scheduler on IA64
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Thu, 14 Jul 2005 11:39:47 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
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Thread-topic: [Xen-devel] RE: [Patch] Fix IDLE issue with sedf scheduler on IA64
> >If you really want to do something like this, it would be 
> much better 
> >just to detect a switch to the idle domain (on whatever CPU dom0
> happens
> >to be running on) and load the register and mm state for 
> dom0 and make 
> >it appear to be the last domain that ran.  The lazy switching logic
> will
> >then take care of things.

> I'm still doubt the really gain of "not switch to idle", 
> which may bring dom0 less period on real job compared to 
> other domains. Saying current model, dom0 is requesting to 
> block in its own idle loop. In this way, dom0's idle loop 
> doesn't occupy any real slice, and the whole period allocated 
> to dom0 is all spent on meaningful job. 

You misunderstood my suggestion. We would still switch to the idle
domain, we just load the dom0 bulk state such that the lazy switch logic
won't won't have to do anything should dom0 be the next domain to run. 


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