Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933171AbZAPLYS (ORCPT ); Fri, 16 Jan 2009 06:24:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756580AbZAPLYF (ORCPT ); Fri, 16 Jan 2009 06:24:05 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:60265 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753989AbZAPLYC (ORCPT ); Fri, 16 Jan 2009 06:24:02 -0500 Date: Fri, 16 Jan 2009 12:23:45 +0100 From: Ingo Molnar To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Andrew Morton , Frederic Weisbecker , Chris Mason Subject: Re: [PATCH 0/2] ftrace: updates to tip Message-ID: <20090116112345.GC20082@elte.hu> References: <20090116004050.273665842@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090116004050.273665842@goodmis.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 Content-Length: 2290 Lines: 66 * Steven Rostedt wrote: > Ingo, > > The first patch is critical, and needs to stay with trace_output.c Not > that critical since trace_output.c is not in mainline yet. > > The second patch gives the ability to stack trace functions. I've been > leery about adding this and still keep it a separate option from the > "stacktrace" that already exists. This is because when enabled with no > filtering, the lag between typing and seeing what is typed can be up to > 10 seconds or more. Btw., is this true even if frame pointers are enabled? When frame pointers are disabled we scan the full kernel stack => that can be quite slow if every kernel function is traced ;-) > I made the function stack trace an option attached to the function > tracer, so it must be enabled after the function tracer has been set. > This still needs to be updated in ftrace.txt. maybe we could drive this via the filter API? Something like: echo "*btrfs*:stacktrace" >> set_filter_functions Would automatically mean that those functions will all generate stacktraces too. Note how safe this API is by default: the filter is used for a narrow scope of functions anwyay. To get it for all kernel functions one would have to do: echo "*:stacktrace" >> set_filter_functions Which one cannot do accidentally. What do you think? > The following patches are in: > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git > > branch: tip/devel > > > Lai Jiangshan (1): > ftrace: fix trace_output > > Steven Rostedt (1): > ftrace: add stack trace to function tracer > > ---- > kernel/trace/trace.c | 26 ++++++++---- > kernel/trace/trace.h | 7 +++ > kernel/trace/trace_functions.c | 84 ++++++++++++++++++++++++++++++++++++++++ > kernel/trace/trace_output.c | 65 +++++++++++++++---------------- > kernel/trace/trace_output.h | 4 +- > 5 files changed, 141 insertions(+), 45 deletions(-) Pulled into tip/tracing/ftrace, thanks Steve! Ingo -- 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/