From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [RFC -v3 PATCH 2/3] sched: add yield_to function
Date: Tue, 04 Jan 2011 18:08:10 +0100
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Cc: Rik van Riel <riel@redhat.com>, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Avi Kiviti <avi@redhat.com>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Mike Galbraith <efault@gmx.de>,
	Chris Wright <chrisw@sous-sol.org>
To: Hillf Danton <dhillf@gmail.com>
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On Wed, 2011-01-05 at 00:51 +0800, Hillf Danton wrote:
> Where is the yield_to callback in the patch for RT schedule class?
> If @p is RT, what could you do? 

RT guests are a pipe dream, you first need to get the hypervisor (kvm in
this case) to be RT, which it isn't. Then you either need to very
statically set-up the host and the guest scheduling constraints (not
possible with RR/FIFO) or have a complete paravirt RT scheduler which
communicates its requirements to the host.