From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760859AbZBYImS (ORCPT ); Wed, 25 Feb 2009 03:42:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753339AbZBYImB (ORCPT ); Wed, 25 Feb 2009 03:42:01 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:35916 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752211AbZBYImA (ORCPT ); Wed, 25 Feb 2009 03:42:00 -0500 Date: Wed, 25 Feb 2009 09:40:00 +0100 From: Ingo Molnar To: Andrew Morton , "H. Peter Anvin" Cc: Steven Rostedt , LKML , Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Theodore Tso , Arjan van de Ven , Pekka Paalanen , Arnaldo Carvalho de Melo , Jason Baron , Martin Bligh , Mathieu Desnoyers , "Frank Ch. Eigler" , KOSAKI Motohiro , Jens Axboe , Masami Hiramatsu , Steven Rostedt Subject: Re: [PATCH 2/4] tracing: add event trace infrastructure Message-ID: <20090225084000.GB9322@elte.hu> References: <20090225025608.956691460@goodmis.org> <20090225025753.798204550@goodmis.org> <20090224194548.3effb746.akpm@linux-foundation.org> <20090224203308.8d623e0b.akpm@linux-foundation.org> <20090225081118.GC15303@elte.hu> <20090225002852.5ef5b869.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090225002852.5ef5b869.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > But we don't do that, because userspace is hard, because we > don't have a delivery process. But nobody has even tried! > [...] Actually, you can do it right now, with the current model: echo raw > /debug/tracing/trace_options echo bin > /debug/tracing/trace_options Reality is that rarely does anyone use it because obviously self-sufficient kernel instrumentation is very convenient to kernel developers, to testers and to bugreporters alike. (Processing kernel details in user-space is also often slower and duplicates code that the kernel already has like symbol lookups.) _Maybe_ some of it (but certainly not all) could be done via klibc - but that got nacked. If you can convince Linus to take klibc and to allow a userspace 'halo' of utilities that are intimate with kernel details into the kernel proper then maybe we could start providing such tools in the kernel proper. Ingo