From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752216AbZHSNuR (ORCPT ); Wed, 19 Aug 2009 09:50:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752043AbZHSNuQ (ORCPT ); Wed, 19 Aug 2009 09:50:16 -0400 Received: from tomts13.bellnexxia.net ([209.226.175.34]:58718 "EHLO tomts13-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752029AbZHSNuO (ORCPT ); Wed, 19 Aug 2009 09:50:14 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AsgEAK+bi0pMRdTz/2dsb2JhbACBUtVdgjOBZwU Date: Wed, 19 Aug 2009 09:50:12 -0400 From: Mathieu Desnoyers To: Ingo Molnar Cc: Josh Stone , Li Zefan , linux-kernel@vger.kernel.org, fweisbec@gmail.com, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, jiayingz@google.com, mbligh@google.com, Jason Baron Subject: Re: [PATCH] tracing: Create generic syscall TRACE_EVENTs Message-ID: <20090819135011.GA8674@Krystal> References: <1250580227-24363-1-git-send-email-jistone@redhat.com> <1250634359-31642-1-git-send-email-jistone@redhat.com> <4A8B5624.9040607@cn.fujitsu.com> <4A8B6C01.1060503@redhat.com> <20090819130517.GB14215@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090819130517.GB14215@elte.hu> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.27.31-grsec (i686) X-Uptime: 09:45:53 up 1 day, 35 min, 2 users, load average: 0.10, 0.36, 0.32 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar (mingo@elte.hu) wrote: > > * Josh Stone wrote: > > > On 08/18/2009 06:32 PM, Li Zefan wrote: > > > It would be much better to see a sample output of these TRACE_EVENTs, > > > so we'll see the what's the output if a syscall has less than 6 args. > > > > > > And I guess it should be "(%lx, %lx, ..., %lx)"? Otherwise I think we'll > > > see some negative values. > > > > Thanks, you're right -- the args should be unsigned long. Whether they > > are hex or decimal doesn't matter to me, but I guess that does make > > pointers easier to spot. > > > > Here's some output that I get on x86_64: > > > > > # tail trace > > > tail-1106 [000] 113218.474657: syscall_enter: NR 2 (7f2d34dd38f0, 0, 7f2d35009010, 5, 4, ffffffffffffffb0) > > > > > > tail-1106 [000] 113218.474809: syscall_enter: NR 5 (3, 7f2d35009040, 7f2d35009040, 5, 4, ffffffffffffffb0) > > > > > > tail-1106 [000] 113218.474855: syscall_enter: NR 9 (0, 50d3ad0, 1, 2, 3, 0) > > > > > > tail-1106 [000] 113218.474946: syscall_enter: NR 3 (3, 7f2d2f9a0000, 5e22, 2, 3, 0) > > > > > > tail-1106 [000] 113218.475673: syscall_enter: NR 2 (7fff5e42a654, 0, 0, 7fff5e429600, 80, 3) > > > > It's very raw indeed, but that's what Ingo asked for. :) The > > extra args show up as whatever happened to be in those registers. > > If the syscalls are handled as a single tracepoint, then they > cannot really have per syscall properties. > > The per syscall tracepoints on the other hand give very finegrained > information. > Hi Ingo, Aiming to identify the event payload type with the event ID alone, I would recommend either: - one tracepoint per syscall argument set types (e.g. same syscall prototype) or - one tracepoint per syscall (seems to be more straightforward) Otherwise getting to fit a struct sockaddr into an integer might be cumbersome. Thanks, Mathieu > Note that via the use of filters one can limit the generic > tracepoint to only output certain syscall NRs, and only with > certain parameters. > > Ingo -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68