Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756876AbYCEQuT (ORCPT ); Wed, 5 Mar 2008 11:50:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754234AbYCEQuE (ORCPT ); Wed, 5 Mar 2008 11:50:04 -0500 Received: from www.tglx.de ([62.245.132.106]:60458 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752075AbYCEQuD (ORCPT ); Wed, 5 Mar 2008 11:50:03 -0500 Date: Wed, 5 Mar 2008 17:45:34 +0100 (CET) From: Thomas Gleixner To: Remy Bohmer cc: David Brownell , Haavard Skinnemoen , akpm@linux-foundation.org, LKML , David Brownell , Nicolas Ferre , Andrew Victor , john stultz Subject: Re: [PATCH] atmel_tc clocksource/clockevent code In-Reply-To: <3efb10970803050317k68da7154w334561cc5efed637@mail.gmail.com> Message-ID: References: <1204636061-6275-1-git-send-email-hskinnemoen@atmel.com> <1204636061-6275-2-git-send-email-hskinnemoen@atmel.com> <3efb10970803041142l4a03dbb9uf11651d4cc7dde96@mail.gmail.com> <200803041247.50877.david-b@pacbell.net> <3efb10970803050317k68da7154w334561cc5efed637@mail.gmail.com> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1142 Lines: 30 On Wed, 5 Mar 2008, Remy Bohmer wrote: > Hello David, > > > Could you elaborate on where that 50-100 usec gets spent? > > Attached I have put a screendump of my ETM debugger. It shows a > complete flow of kernel function-calls of what happens on a timer > interrupt. In this example the complete sequence takes about 154 us. > Notice that the ETM is non-intrusive, and that the times are real and > accurate in this trace. (you can even see the effects of CPU-caches, > sometimes the same code just runs faster) Is there any chance to convert this to a text table? Following that png is pretty hard. > So, hires timestamps -> really really welcome. > hires timers -> there should be a (configurable) minimal resolution > that fits the hardware to not overload the CPU. clockevents let you set a minimum delta already. This can be set at runtime before registering the device. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/