From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262002AbVFVUNH (ORCPT ); Wed, 22 Jun 2005 16:13:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262043AbVFVUNA (ORCPT ); Wed, 22 Jun 2005 16:13:00 -0400 Received: from smtp.lnxw.com ([207.21.185.24]:34571 "EHLO smtp.lnxw.com") by vger.kernel.org with ESMTP id S262002AbVFVUI7 (ORCPT ); Wed, 22 Jun 2005 16:08:59 -0400 Date: Wed, 22 Jun 2005 13:15:36 -0700 To: Karim Yaghmour Cc: "Bill Huey (hui)" , Kristian Benoit , linux-kernel@vger.kernel.org, paulmck@us.ibm.com, andrea@suse.de, tglx@linutronix.de, mingo@elte.hu, pmarques@grupopie.com, bruce@andrew.cmu.edu, nickpiggin@yahoo.com.au, ak@muc.de, sdietrich@mvista.com, dwalker@mvista.com, hch@infradead.org, akpm@osdl.org, rpm@xenomai.org Subject: Re: PREEMPT_RT vs I-PIPE: the numbers, part 2 Message-ID: <20050622201536.GA14052@nietzsche.lynx.com> References: <1119287612.6863.1.camel@localhost> <20050620183115.GA27028@nietzsche.lynx.com> <42B98B20.7020304@opersys.com> <20050622192927.GA13817@nietzsche.lynx.com> <42B9C5D1.3020403@opersys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42B9C5D1.3020403@opersys.com> User-Agent: Mutt/1.5.9i From: Bill Huey (hui) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 22, 2005 at 04:10:57PM -0400, Karim Yaghmour wrote: > Bill Huey (hui) wrote: > > FreeBSD went through some slow down when they moved to SMPng, but not > > the kind of numbers you show for things surrounding the network stack. > > Something clearly bad happened. > > Note that the numbers are not freak accidents, they are consistent > accross the various setups. So in total, that's 15 LMbench runs, > all showing consistent _severe_ cost for preempt_rt. And this despite Yeah, I looked at the numbers more carefully and it's clearly showing some problems. There is a significant context switch penalty with irq-threads and I wouldn't surprise if this is what's going on. bill