Message-ID: <4C060ACC.7080103@zytor.com>
Date: Wed, 02 Jun 2010 00:39:56 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Valdis.Kletnieks@vt.edu
CC: Avi Kivity <avi@redhat.com>, Andi Kleen <andi@firstfloor.org>,
       Gleb Natapov <gleb@redhat.com>, linux-kernel@vger.kernel.org,
       kvm@vger.kernel.org, mingo@elte.hu, npiggin@suse.de, tglx@linutronix.de,
       mtosatti@redhat.com
Subject: Re: [PATCH] use unfair spinlock when running on hypervisor.
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>
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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

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