From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [RFC PATCH 2/3] sched: add yield_to function Date: Fri, 03 Dec 2010 10:35:25 -0500 Message-ID: <4CF90E3D.7090103@redhat.com> References: <20101202144129.4357fe00@annuminas.surriel.com> <20101202144423.3ad1908d@annuminas.surriel.com> <1291355656.7633.124.camel@marge.simson.net> <20101203134618.GG27994@linux.vnet.ibm.com> <1291387511.7992.15.camel@marge.simson.net> <4CF90341.4020101@redhat.com> <1291388987.7992.27.camel@marge.simson.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: vatsa@linux.vnet.ibm.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Avi Kiviti , Peter Zijlstra , Ingo Molnar , Anthony Liguori To: Mike Galbraith Return-path: In-Reply-To: <1291388987.7992.27.camel@marge.simson.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 12/03/2010 10:09 AM, Mike Galbraith wrote: > On Fri, 2010-12-03 at 09:48 -0500, Rik van Riel wrote: >> On 12/03/2010 09:45 AM, Mike Galbraith wrote: >> >>> I'll have to go back and re-read that. Off the top of my head, I see no >>> way it could matter which container the numbers live in as long as they >>> keep advancing, and stay in the same runqueue. (hm, task weights would >>> have to be the same too or scaled. dangerous business, tinkering with >>> vruntimes) >> >> They're not necessarily in the same runqueue, the >> VCPU that is given time might be on another CPU >> than the one that was spinning on a lock. > > I don't think pumping vruntime cross cfs_rq would be safe, for the > reason noted (et al). No competition means vruntime is meaningless. > Donating just advances a clock that nobody's looking at. Do you have suggestions on what I should do to make this yield_to functionality work? I'm willing to implement pretty much anything the scheduler people will be happy with :) -- All rights reversed