From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: Will Xen 4.0 release use the pv-ops kernel despite
	it's performance hit
Date: Mon, 21 Dec 2009 13:41:46 -0800
Message-ID: <4B2FEB9A.8010401@goop.org>
References: <8686c3cd0912200941k2effc65ao5e1534c9344f8b71@mail.gmail.com>	<C7544D70.4D90%keir.fraser@eu.citrix.com>
	<8686c3cd0912202216y33385cb2p62ef12d4807ceabf@mail.gmail.com>
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To: Tom Rotenberg <tom.rotenberg@gmail.com>
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On 12/20/2009 10:16 PM, Tom Rotenberg wrote:
> I just thought i saw Jeremy's mail about changing the APIC logic in
> Xen to conform to the pv-ops kernel, which i thought will cause new
> Xen not to work with old dom0 kernel. This isn't the case?
>    

No.  Future pvops dom0 kernels will require Xen >= 4.0.  Xen 4.0 will 
still support older dom0 kernels.

BTW, I haven't measured pvops dom0 performance, but there's no 
particular reason to believe there'll be a big hit (the performance hit 
I was talking about refers to the overhead of fork/exec-heavy workloads, 
which is very unlike dom0's workload).

     J