From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756236AbYK0ONz (ORCPT ); Thu, 27 Nov 2008 09:13:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753417AbYK0ONq (ORCPT ); Thu, 27 Nov 2008 09:13:46 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:41766 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753297AbYK0ONp (ORCPT ); Thu, 27 Nov 2008 09:13:45 -0500 Date: Thu, 27 Nov 2008 15:13:31 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Peter Zijlstra , Frederic Weisbecker , Tim Bird , Linux Kernel Subject: Re: [PATCH] tracing/function-branch-tracer: enhancements for the trace output Message-ID: <20081127141331.GA28479@elte.hu> References: <492DEDE9.9010109@gmail.com> <20081127103424.GA9132@elte.hu> <1227783300.4454.1410.camel@twins> <20081127112953.GA23702@elte.hu> 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: > > On Thu, 27 Nov 2008, Ingo Molnar wrote: > > > > > mockup: > > > > ---------------------------------------------------------------- > > CPU) task-PID | cost | function > > ---------------------------------------------------------------- > > > > 0) bash-54320 | | sys_read() { > > 0) bash-54320 | 0.331 us | fget_light(); > > 0) bash-54320 | | vfs_read() { > > 0) mycomman-1234 | | rw_verify_area() { > > 0) mycomman-1234 | 121.444 us | func(); > > > > Note some details: > > > > 1) longer comm names can be stripped off at 7 chars - 7 chars is > > enough to recognize most of the things and the PID is good enough > > for extra separation) > > > > 2) the ssssssss-12345 task identifier is _center_ aligned. It's a rare > > alignment case but useful here: most people look at the command > > portion and the whole string must be greppable and useful in traces > > as an identifier - so right-aligning the PID is not a good > > solution. > > > > 3) there's vertical separation after the task portion as well. This > > helps us ignore the task portion when we want to look at only the > > code and the cost of it. (the common case) > > > > > comm/pid only in the separator is useless, you cannot grep stuff > > > like that, also, what's up with those '8's ? > > > > yeah, that context-switch separator is horrible. > > > > We can keep the separator, but as something saner, like: > > > > --------------------------------------------------------- > > CPU) cost | function > > --------------------------------------------------------- > > > > 0) | sys_read() { > > 0) 0.331 us | fget_light(); > > 0) | vfs_read() { > > 0) | rw_verify_area() { > > 0) | security_file_permission() { > > 0) 0.306 us | cap_file_permission(); > > 0) 0.300 us | cap_file_permission(); > > 0) 8.909 us | } > > 0) 0.993 us | } > > 0) 11.649 us | } > > 0) | do_sync_read() { > > . ------------------------- > > 0) ==> [ bash-2794 => cat-1234 ] > > ------------------------- > > > > 0) | __sock_recvmsg() { > > 0) | security_socket_recvmsg() { > > 0) 100.319 us | cap_socket_recvmsg(); > > --------------------------------------------------------- > > Yes please. I like the separator better. Sure, we could add a trace_option > that will let us print the name on all lines, which will make it grepable > better. But this is better to see when the switch happens. > > Also, Frederic could use my ftrace_trace_pid to filter only on a > single thread. But that will need to wait till we figure out this > namespace issue. Note that your PID filter is in tip/tracing/core already, so Frederic can make use of it if he wishes to. Changing it to struct pid (whenever that happens) will not change its functionality. Ingo