From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752190Ab1ADQyT (ORCPT ); Tue, 4 Jan 2011 11:54:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55144 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005Ab1ADQyS (ORCPT ); Tue, 4 Jan 2011 11:54:18 -0500 Message-ID: <4D2350AE.60302@redhat.com> Date: Tue, 04 Jan 2011 11:54:06 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc13 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Hillf Danton CC: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Avi Kiviti , Srivatsa Vaddagiri , Peter Zijlstra , Mike Galbraith , Chris Wright Subject: Re: [RFC -v3 PATCH 2/3] sched: add yield_to function References: <20110103162637.29f23c40@annuminas.surriel.com> <20110103162918.577a9620@annuminas.surriel.com> <4D234E60.3010804@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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