From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754669AbYIXUhm (ORCPT ); Wed, 24 Sep 2008 16:37:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752202AbYIXUhe (ORCPT ); Wed, 24 Sep 2008 16:37:34 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:44590 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751652AbYIXUhe (ORCPT ); Wed, 24 Sep 2008 16:37:34 -0400 Date: Wed, 24 Sep 2008 13:37:20 -0700 (PDT) Message-Id: <20080924.133720.72895701.davem@davemloft.net> To: torvalds@linux-foundation.org Cc: rostedt@goodmis.org, mbligh@google.com, peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, akpm@linux-foundation.org, prasad@linux.vnet.ibm.com, compudj@krystal.dyndns.org, fche@redhat.com, dwilder@us.ibm.com, hch@lst.de, zanussi@comcast.net, srostedt@redhat.com Subject: Re: [RFC PATCH 1/3] Unified trace buffer From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.1 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds Date: Wed, 24 Sep 2008 13:23:47 -0700 (PDT) > So I'd like the thing to have small headers, and be designed from the > start to have small headers. Small headers are good, but I'd suggest making sure there is an "offset" or similar field in there. Not that I want to encourage frequent changes to header layout, but if you do need to add something, then this offset field allows you to do so while keeping existing analysis tools working. They will just ignore the new information in the headers, but they will still be able to get at the data bits using the offset.