From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755448AbYG2HIi (ORCPT ); Tue, 29 Jul 2008 03:08:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752630AbYG2HIa (ORCPT ); Tue, 29 Jul 2008 03:08:30 -0400 Received: from moutng.kundenserver.de ([212.227.126.171]:57949 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752596AbYG2HI3 (ORCPT ); Tue, 29 Jul 2008 03:08:29 -0400 Message-ID: <488EC1DA.7000708@manoweb.com> Date: Tue, 29 Jul 2008 00:08:10 -0700 From: Alessio Sangalli User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Iwo Mergler CC: linux-kernel Subject: Re: interrupt overhead on ARM architecture References: <488E7F08.7060309@manoweb.com> <488EA477.7070101@call-direct.com.au> In-Reply-To: <488EA477.7070101@call-direct.com.au> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Provags-ID: V01U2FsdGVkX19uImL3OdVpCphg4lU7ZPtAQvec0f65A19NEFx 05KFdCTOs1uDs+aIule6dPDqx2VXil5rGTIS4pPrgs5qhddB/R XXpVieWyyfnfrP1aYC2eA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Iwo Mergler wrote: > In other words, you can't even measure the latency on a particular > system and then assume it will stay anywhere near constant. Comparing > different systems with the same processor core is hopeless. Everything makes perfect sense. For this reason, I am willing to do some tests on my own platform. How would you suggest to proceed? I would need an extremely accurate way to measure time to begin with and then: - read that time reference - generate an interrupt by placing some data in a device or so - reading again that time reference as first thing in the ISR - save the result - do the above in various scenarios, with different drivers enabled, CPU load, etc etc bye Alessio