From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753842AbZEIPjQ (ORCPT ); Sat, 9 May 2009 11:39:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751945AbZEIPi7 (ORCPT ); Sat, 9 May 2009 11:38:59 -0400 Received: from mx1.redhat.com ([66.187.233.31]:41048 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778AbZEIPi6 (ORCPT ); Sat, 9 May 2009 11:38:58 -0400 Date: Sat, 9 May 2009 11:36:29 -0400 From: "Frank Ch. Eigler" To: Ingo Molnar Cc: Jason Baron , Tom Zanussi , linux-kernel@vger.kernel.org, fweisbec@gmail.com, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, mathieu.desnoyers@polymtl.ca, jiayingz@google.com, mbligh@google.com, roland@redhat.com Subject: Re: [RFC] convert ftrace syscall tracer to TRACE_EVENT() Message-ID: <20090509153629.GC29911@redhat.com> References: <20090508210347.GA3121@redhat.com> <20090509083737.GE3656@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090509083737.GE3656@elte.hu> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi - On Sat, May 09, 2009 at 10:37:37AM +0200, Ingo Molnar wrote: > [...] > Firstly, it adds two new tracepoints to every system call. That is > unnecessary - we already have the TIF flag based callbacks, and we > can use the existing syscall attributes table to get to tracepoints > - without slow down (or impacting) the fast path in any way. > [...] However, as the TIF_SYSCALL_FTRACE and/or TIF_SYSCALL_TRACE flags are tied to a single consumer, it would limit the usefulness of the naturally multiple-client tracepoints, if they were made conditional on them. Would you be interested in a proper reference-counting API? - FChE