Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756226Ab2JCR0Y (ORCPT ); Wed, 3 Oct 2012 13:26:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8531 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755168Ab2JCR0W (ORCPT ); Wed, 3 Oct 2012 13:26:22 -0400 Message-ID: <506C7524.2010103@redhat.com> Date: Wed, 03 Oct 2012 19:25:56 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 MIME-Version: 1.0 To: Raghavendra K T CC: Peter Zijlstra , "H. Peter Anvin" , Marcelo Tosatti , Ingo Molnar , Rik van Riel , Srikar , "Nikunj A. Dadhania" , KVM , Jiannan Ouyang , chegu vinod , "Andrew M. Theurer" , LKML , Srivatsa Vaddagiri , Gleb Natapov , Andrew Jones Subject: Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler References: <1348486479.11847.46.camel@twins> <50604988.2030506@linux.vnet.ibm.com> <1348490165.11847.58.camel@twins> <50606050.309@linux.vnet.ibm.com> <1348494895.11847.64.camel@twins> <50606B33.1040102@linux.vnet.ibm.com> <5061B437.8070300@linux.vnet.ibm.com> <5064101A.5070902@redhat.com> <50643745.6010202@linux.vnet.ibm.com> <506440AF.9080202@redhat.com> <20121003142942.GB15253@linux.vnet.ibm.com> In-Reply-To: <20121003142942.GB15253@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1433 Lines: 47 On 10/03/2012 04:29 PM, Raghavendra K T wrote: > * Avi Kivity [2012-09-27 14:03:59]: > >> On 09/27/2012 01:23 PM, Raghavendra K T wrote: >> >> > [...] >> > 2) looking at the result (comparing A & C) , I do feel we have >> > significant in iterating over vcpus (when compared to even vmexit) >> > so We still would need undercommit fix sugested by PeterZ (improving by >> > 140%). ? >> >> Looking only at the current runqueue? My worry is that it misses a lot >> of cases. Maybe try the current runqueue first and then others. >> > > Okay. Do you mean we can have something like > > + if (rq->nr_running == 1 && p_rq->nr_running == 1) { > + yielded = -ESRCH; > + goto out_irq; > + } > > in the Peter's patch ? > > ( I thought lot about && or || . Both seem to have their own cons ). > But that should be only when we have short term imbalance, as PeterZ > told. I'm missing the context. What is p_rq? What I mean was: if can_yield_to_process_in_current_rq do that else if can_yield_to_process_in_other_rq do that else return -ESRCH -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/