From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760492AbYHOPkw (ORCPT ); Fri, 15 Aug 2008 11:40:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760206AbYHOPke (ORCPT ); Fri, 15 Aug 2008 11:40:34 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:37469 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760176AbYHOPkd (ORCPT ); Fri, 15 Aug 2008 11:40:33 -0400 Date: Fri, 15 Aug 2008 17:40:14 +0200 From: Ingo Molnar To: Steven Rostedt Cc: LKML , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Linus Torvalds Subject: Re: [PATCH v2] ftrace: dump out ftrace buffers to console on panic Message-ID: <20080815154014.GD27955@elte.hu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 * Steven Rostedt wrote: > [ > Changes since -v1: > Got alpine to send correctly (as well as spell check working). > Removed config option. > Moved the static variables into ftrace_dump itself. > Gave printk a log level. > ] > > At OLS I had a lot of interest to be able to have the ftrace buffers > dumped on panic. Usually one would expect to uses kexec and examine > the buffers after a new kernel is loaded. But sometimes the resources > do not permit kdump and kexec, so having an option to still see the > sequence of events up to the crash is very advantageous. > > This patch adds the option to have the ftrace buffers dumped to the > console in the latency_trace format on a panic. When the option is > set, the default entries per CPU buffer are lowered to 16384, since > the writing to the serial (if that is the console) may take an awful > long time otherwise. we had this in the latency tracer - so it's a very useful feature. Applied to tip/tracing/ftrace, thanks Steve. Ingo