From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [RFC -v3 PATCH 2/3] sched: add yield_to function Date: Tue, 04 Jan 2011 11:54:06 -0500 Message-ID: <4D2350AE.60302@redhat.com> References: <20110103162637.29f23c40@annuminas.surriel.com> <20110103162918.577a9620@annuminas.surriel.com> <4D234E60.3010804@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Avi Kiviti , Srivatsa Vaddagiri , Peter Zijlstra , Mike Galbraith , Chris Wright To: Hillf Danton Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 01/04/2011 11:51 AM, Hillf Danton wrote: >> Wouldn't that break for FIFO and RR tasks? >> >> There's a reason all the scheduler folks wanted a >> per-class yield_to_task function :) >> > > Where is the yield_to callback in the patch for RT schedule class? > If @p is RT, what could you do? If the user chooses to overcommit the CPU with realtime tasks, the user cannot expect realtime response. For realtime, I have not implemented the yield_to callback at all because it would probably break realtime semantics and I assume people will not overcommit the CPU with realtime tasks anyway. I could see running a few realtime guests on a system, with the number of realtime VCPUs not exceeding the number of physical CPUs. -- All rights reversed