From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Re: Xen spinlock questions Date: Thu, 07 Aug 2008 08:47:51 -0700 Message-ID: <489B1927.8070304@goop.org> References: <4896F39A.76E4.0078.0@novell.com> <48975A30.2080408@goop.org> <48981005.76E4.0078.0@novell.com> <4898976A.3080406@goop.org> <48996BB8.76E4.0078.0@novell.com> <48996536.1030303@goop.org> <48998C7E.76E4.0078.0@novell.com><48998C7E.76E4.0078.0@novell.com> <489A07E1.6070808@goop.org> <489ABE89.76E4.0078.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <489ABE89.76E4.0078.0@novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: xen-devel@lists.xensource.com, Keir Fraser List-Id: xen-devel@lists.xenproject.org Jan Beulich wrote: >>>> Jeremy Fitzhardinge 06.08.08 22:21 >>> >>>> >> Jan Beulich wrote: >> >>>> In my tests, I only see it fall into the slow path a couple of thousand >>>> times per cpu for a kernbench run. >>>> >>>> >>> Hmm, that's different then for me. Actually, I see a significant spike at >>> modpost stage 2, when all the .ko-s get linked. The (spinlock) interrupt >>> rate gets up to between 1,000 and 2,000 per CPU and second. >>> >>> >> BTW, how much contention for CPUs was there? >> > > In Xen or the kernel? So far these are all Dom0-only measurements, so > in Xen there should be no contention. > OK. The spinlock results are most interesting when there's contention for physical cpus between domains. > To answer your other mail's question: It's defconfig builds I'm using. > [SuSE defconfigs] Presumably that has a lot enabled as modules. J