From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 20 Sep 2001 16:36:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 20 Sep 2001 16:36:19 -0400 Received: from maile.telia.com ([194.22.190.16]:2528 "EHLO maile.telia.com") by vger.kernel.org with ESMTP id ; Thu, 20 Sep 2001 16:36:13 -0400 Message-Id: <200109202036.f8KKaUv18307@maile.telia.com> Content-Type: text/plain; charset="iso-8859-1" From: Roger Larsson To: george anzinger , Roger Larsson Subject: Re: [PATCH] latency-profiling Date: Thu, 20 Sep 2001 22:31:40 +0200 X-Mailer: KMail [version 1.3.1] Cc: linux-kernel@vger.kernel.org, Robert Love In-Reply-To: <200109200609.f8K69uQ26778@mailc.telia.com> <3BAA49B5.E02FA5E7@mvista.com> In-Reply-To: <3BAA49B5.E02FA5E7@mvista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursdayen den 20 September 2001 21.55, george anzinger wrote: > Roger Larsson wrote: > > Hi, > > > > I ported my old latency-profiling patch to 2.4.10-pre10 with > > the reschedulable kernel patch. (I have not checked that it is > > preemption safe itself...) > > > > This patch works a little different from Robert Loves. > > Since it samples the execution location at ticks. > > It is possible to instrument an ordinary kernel too... > > It gives experienced latencies rather than potential latencies, but more > important from the developer/maintainers point of view, "Robert Loves" > patch provides information on the bad guys, i.e. the reason for the long > latency, which, hopefully, will allow them to be addressed by competent > maintainers. > Yes, but my technique can be applied to any kernel. It does not require an preemptible kernel... I.e. measures time from the moment a reschedulation was reqired to it is actually done - independent of how it is done... And if you run something that needs periodic reshedules you will detect actual problems. And thus it can be used as a bench, it is hard to describe skips in music, textual data is easier to send by mail... But I agree that Roberts is better to find the critical ones! /RogerL -- Roger Larsson Skellefteċ Sweden