From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753642Ab1L0Ket (ORCPT ); Tue, 27 Dec 2011 05:34:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24065 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753210Ab1L0Ker (ORCPT ); Tue, 27 Dec 2011 05:34:47 -0500 Message-ID: <4EF99F3A.6070203@redhat.com> Date: Tue, 27 Dec 2011 12:34:34 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 MIME-Version: 1.0 To: Nikunj A Dadhania CC: Ingo Molnar , peterz@infradead.org, linux-kernel@vger.kernel.org, vatsa@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS References: <20111219083141.32311.9429.stgit@abhimanyu.in.ibm.com> <20111219112326.GA15090@elte.hu> <87sjke1a53.fsf@abhimanyu.in.ibm.com> <4EF1B85F.7060105@redhat.com> <877h1o9dp7.fsf@linux.vnet.ibm.com> <20111223103620.GD4749@elte.hu> <4EF701C7.9080907@redhat.com> <87vcp4t45p.fsf@linux.vnet.ibm.com> <877h1iu2md.fsf@linux.vnet.ibm.com> <4EF98D29.1080809@redhat.com> <87ty4mic23.fsf@abhimanyu.in.ibm.com> <4EF99532.3010803@redhat.com> <87obuuiatw.fsf@abhimanyu.in.ibm.com> In-Reply-To: <87obuuiatw.fsf@abhimanyu.in.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 On 12/27/2011 12:10 PM, Nikunj A Dadhania wrote: > On Tue, 27 Dec 2011 11:51:46 +0200, Avi Kivity wrote: > > On 12/27/2011 11:44 AM, Nikunj A Dadhania wrote: > > > > > I am seeing a drop of ~44% when setting yield_on_hlt = 0 > > > > > > > > > > > > > A drop of 44% of what? > > > > > > > records/sec > > > > > > Ebizzy - 2VM running in parallel, both having gang scheduling enabled. > > > > > > yield_on_hlt=1 yield_on_hlt=0 > > > EbzyRecords/sec 41955.50 23285.00 -44 > > > > > > > > > > Interesting, are you overcommitting vcpus? > > > Yes(1:2). On a 8cpu machine, have 2VMs running, which is 8vcpus each. Ah, yield_on_hlt=0 isn't any good with overcommit. The vcpu stays scheduled when idle, so other vcpus don't get to use its cpu time. -- error compiling committee.c: too many arguments to function