From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261750AbVFVRWL (ORCPT ); Wed, 22 Jun 2005 13:22:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261760AbVFVRSp (ORCPT ); Wed, 22 Jun 2005 13:18:45 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:2705 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S261713AbVFVRRp (ORCPT ); Wed, 22 Jun 2005 13:17:45 -0400 Subject: Re: PREEMPT_RT vs I-PIPE: the numbers, part 2 From: Lee Revell To: karim@opersys.com Cc: paulmck@us.ibm.com, Kristian Benoit , linux-kernel@vger.kernel.org, bhuey@lnxw.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 In-Reply-To: <42B9845B.8030404@opersys.com> References: <1119287612.6863.1.camel@localhost> <20050621015542.GB1298@us.ibm.com> <42B77B8C.6050109@opersys.com> <20050622011931.GF1324@us.ibm.com> <42B9845B.8030404@opersys.com> Content-Type: text/plain Date: Wed, 22 Jun 2005 13:17:40 -0400 Message-Id: <1119460661.491.31.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2005-06-22 at 11:31 -0400, Karim Yaghmour wrote: > max_ipipe_delay = 27.5us > average_ipipe_delay = 7us > max_preempt_delay = 55us - max_ipipe_delay = 27.5us > average_preempt_delay = 14 us - average_ipipe_delay = 7us Ingo, what's the status of putting irq 0 back in a thread with PREEMPT_RT? IIRC this had some adverse (maybe unfixable?) effects so it was disabled a few months ago. I don't think there's much point in comparing i-pipe to PREEMPT_RT if we know that 21usec pipeline effect from the timer IRQ (see list archives) is still there. Lee