From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [PATCH] qemu-kvm: response to SIGUSR1 to start/stop a VCPU (v2) Date: Wed, 01 Dec 2010 12:26:36 -0500 Message-ID: <4CF6854C.4020500@redhat.com> References: <1290530963-3448-1-git-send-email-aliguori@us.ibm.com> <4CECCA39.4060702@redhat.com> <4CED1A23.9030607@linux.vnet.ibm.com> <4CED1FD3.1000801@redhat.com> <20101201123742.GA3780@linux.vnet.ibm.com> <4CF6460C.5070604@redhat.com> <20101201161221.GA8073@linux.vnet.ibm.com> <1291220718.32004.1696.camel@laptop> <20101201171758.GA8514@sequoia.sous-sol.org> <1291224176.32004.1763.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Chris Wright , vatsa@linux.vnet.ibm.com, Avi Kivity , Anthony Liguori , qemu-devel@nongnu.org, kvm@vger.kernel.org, Ingo Molnar , Mike Galbraith To: Peter Zijlstra Return-path: Received: from mx1.redhat.com ([209.132.183.28]:29561 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755928Ab0LASo2 (ORCPT ); Wed, 1 Dec 2010 13:44:28 -0500 In-Reply-To: <1291224176.32004.1763.camel@laptop> Sender: kvm-owner@vger.kernel.org List-ID: On 12/01/2010 12:22 PM, Peter Zijlstra wrote: > On Wed, 2010-12-01 at 09:17 -0800, Chris Wright wrote: >> Directed yield and fairness don't mix well either. You can end up >> feeding the other tasks more time than you'll ever get back. > > If the directed yield is always to another task in your cgroup then > inter-guest scheduling fairness should be maintained. > > Yes, but not the inter-vcpu fairness. The pause loop exiting & directed yield patches I am working on preserve inter-vcpu fairness by round robining among the vcpus inside one KVM guest. -- All rights reversed