From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261839AbVFKWgw (ORCPT ); Sat, 11 Jun 2005 18:36:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261838AbVFKWgv (ORCPT ); Sat, 11 Jun 2005 18:36:51 -0400 Received: from opersys.com ([64.40.108.71]:59398 "EHLO www.opersys.com") by vger.kernel.org with ESMTP id S261839AbVFKWgr (ORCPT ); Sat, 11 Jun 2005 18:36:47 -0400 Message-ID: <42AB662B.4010104@opersys.com> Date: Sat, 11 Jun 2005 18:31:07 -0400 From: Karim Yaghmour Reply-To: karim@opersys.com Organization: Opersys inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040805 Netscape/7.2 X-Accept-Language: en-us, en, fr, fr-be, fr-ca, fr-fr MIME-Version: 1.0 To: Ingo Molnar CC: Kristian Benoit , linux-kernel@vger.kernel.org, paulmck@us.ibm.com, bhuey@lnxw.com, andrea@suse.de, tglx@linutronix.de, 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 ADEOS: the numbers, part 1 References: <42AA6A6B.5040907@opersys.com> <20050611191448.GA24152@elte.hu> In-Reply-To: <20050611191448.GA24152@elte.hu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > how were interrupt response times measured, precisely? What did the > target (measured) system have to do to respond to an interrupt? Did you > use the RTC to measure IRQ latencies? The logger used two TSC values. One prior to shooting the interrupt to the target, and one when receiving the response. Responding to an interrupt meant that a driver was hooked to the target's parallel port interrupt and simply acted by toggling an output pin on the parallel port, which in turn was hooked onto the logger's parallel port in a similar fashion. We'll post the code for all components (both logger and target) for everyone to review. There's no validity in any tests if others can't analyze/criticize/ duplicate. Karim -- Author, Speaker, Developer, Consultant Pushing Embedded and Real-Time Linux Systems Beyond the Limits http://www.opersys.com || karim@opersys.com || 1-866-677-4546