From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406Ab1GGAab (ORCPT ); Wed, 6 Jul 2011 20:30:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:51483 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754550Ab1GGAaa (ORCPT ); Wed, 6 Jul 2011 20:30:30 -0400 Message-ID: <4E14FE1A.9000003@zytor.com> Date: Wed, 06 Jul 2011 17:30:18 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Frederic Weisbecker CC: David Sharp , Vaibhav Nagarnaik , Thomas Gleixner , Ingo Molnar , Steven Rostedt , Michael Rubin , x86@kernel.org, "linux-kernel@vger.kernel.org" , Jiaying Zhang Subject: Re: [PATCH v2] trace: Add x86 irq vector entry/exit tracepoints References: <1304107962-18576-1-git-send-email-vnagarnaik@google.com> <1306877298-31713-1-git-send-email-vnagarnaik@google.com> <20110531235957.GB5256@somewhere.redhat.com> <20110616030200.GC18579@somewhere.redhat.com> <4E14F31B.4080102@zytor.com> <20110706235613.GA21115@somewhere> <4E14F797.8070501@zytor.com> <20110707002512.GB21115@somewhere> In-Reply-To: <20110707002512.GB21115@somewhere> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/06/2011 05:25 PM, Frederic Weisbecker wrote: > > I'm suggesting two things: > > 1) If every arch implement a tracepoint for a generic event, then move the tracepoint > to the generic code. I believe that part is not very controversial. > Agreed -- as long as it doesn't mean breaking the flow for specific arches. > 2) If every arch implement a common event that is not implemented in core code (I believe > it was the case for reschedule_interrupt few times ago but changed lately) then try > to have a common tracepoint for every archs if possible. So that we don't have > thousand names for the same event, or different parameters name when those parameters and the > event semantic are exactly the same amongst every architecture. Agreed as well. > Trace events are irresponsible anyway because they involve that "ABI not really stable but tools > rely on it so...well...)". I'm not sure the above points make the situation worse though. Probably > the cases that fit in 2) need to be carefully checked to ensure they really fit in 2). Yes, it was much more of a generic concern. However, it is very important that people have a correct idea about what the stability of something like tracepoint is -- or we'll end up in a situation where we can never change the kernel because anything is suddenly "user space visible." -hpa