From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: RE: rdtsc strangeness on upstream kernel Date: Mon, 19 Jul 2010 17:34:16 -0700 Message-ID: <4C44EF08.3070103@goop.org> References: <0784c7e7-1e9c-4abd-8e90-837051fe6b8b@default 4C44E123.3030308@goop.org 441eecef-5758-4c3f-924e-74823b7cb776@default> <681683ff-677b-4709-911e-3d90d7dbed7c@default> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <681683ff-677b-4709-911e-3d90d7dbed7c@default> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Dan Magenheimer Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 07/19/2010 04:55 PM, Dan Magenheimer wrote: >> With vcpus=2, timer0 goes up to about 2000 irq/sec on CPU0 >> and timer1 on CPU1 is the same while rdtsc/sec is about 20000. >> > No, wait, correct that...timer0 and timer1 are 1000 irq/sec. > (I was using "watch -d" which defaults to updating every > two seconds, not every second.) > > >> Is it possible that the timer interrupt is using rdtsc >> five times each interrupt? >> > TEN times each interrupt. > Do you have any other debugging/tracing enabled? CONFIG_XEN_DEBUG_FS for example? 10 sounds a little high, but not necessarily completely unreasonable, especially if there's tracing/debugging on. J