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Re: [Xen-devel] Re: IDLE domain is scheduled more than dom0

To: Andrew Theurer <habanero@xxxxxxxxxx>
Subject: Re: [Xen-devel] Re: IDLE domain is scheduled more than dom0
From: Stephan Diestelhorst <sd386@xxxxxxxxx>
Date: Sat, 09 Jul 2005 19:14:06 +0100
Cc: Dan Magenheimer <dan.magenheimer@xxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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Andrew Theurer schrieb:

>On Friday 08 July 2005 09:53, Dan Magenheimer wrote:
>>>     Shouldn't IDLE domain not be scheduled for most time? Because
>>>idle task will call into PAL for power save on XEN/IA64, the
>>>performance is really, really bad to boot Dom0. The net effect is
>>>about ten times slower. After adding "sched=bvt", everything back
>>>to normal.
>>If the sedf scheduler is scheduling the idle domain when
>>domain0 is runnable, surely this is affecting performance
>>on x86 also and is a bug that should be fixed?
>>Has anyone done any performance testing (on x86) since
>>sedf was checked in as the default?
>Just tried launching some cpu bound tasks in dom0, and I get only 75% 
>cpu util for dom0.  I'll try the other domain scheduler and see if it 
>clears it up.
> cpu0:  [075.3] d0-0[075.3]
> cpu1:  [075.3] d0-1[075.3]
> cpu2:  [075.3] d0-2[075.3]
> cpu3:  [074.8] d0-3[074.8]
This is the current default behaviour of domain 0, it gets 75% of the
CPU time and no slack time. This is easily changeable, and I guess it is
usefull to do so!

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