From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH] use unfair spinlock when running on hypervisor. Date: Wed, 02 Jun 2010 00:39:56 -0700 Message-ID: <4C060ACC.7080103@zytor.com> References: <20100601093515.GH24302@redhat.com> <87sk56ycka.fsf@basil.nowhere.org> <20100601162414.GA6191@redhat.com> <20100601163807.GA11880@basil.fritz.box> <4C053ACC.5020708@redhat.com> <10707.1275413954@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Andi Kleen , Gleb Natapov , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mingo@elte.hu, npiggin@suse.de, tglx@linutronix.de, mtosatti@redhat.com To: Valdis.Kletnieks@vt.edu Return-path: In-Reply-To: <10707.1275413954@localhost> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 06/01/2010 10:39 AM, Valdis.Kletnieks@vt.edu wrote: > On Tue, 01 Jun 2010 19:52:28 +0300, Avi Kivity said: >> On 06/01/2010 07:38 PM, Andi Kleen wrote: >>>>> Your new code would starve again, right? >>> Try it on a NUMA system with unfair memory. > >> We are running everything on NUMA (since all modern machines are now >> NUMA). At what scale do the issues become observable? > > My 6-month-old laptop is NUMA? Comes as a surprise to me, and to the > perfectly-running NUMA=n kernel I'm running. > > Or did you mean a less broad phrase than "all modern machines"? > All modern multisocket machines, unless configured in interleaved memory mode. -hpa