From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756668AbZJGGXN (ORCPT ); Wed, 7 Oct 2009 02:23:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754482AbZJGGXN (ORCPT ); Wed, 7 Oct 2009 02:23:13 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:38506 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753953AbZJGGXM (ORCPT ); Wed, 7 Oct 2009 02:23:12 -0400 Date: Wed, 7 Oct 2009 08:22:04 +0200 From: Ingo Molnar To: Frederic Weisbecker Cc: Peter Zijlstra , Arnaldo Carvalho de Melo , Paul Mackerras , Mike Galbraith , LKML Subject: Re: [RFC][PATCH] perf tools: Merge trace.info content into perf.data Message-ID: <20091007062204.GE21673@elte.hu> References: <20091006213643.GA5343@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091006213643.GA5343@nowhere> User-Agent: Mutt/1.5.18 (2008-05-17) 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=3.2.5 -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 * Frederic Weisbecker wrote: > Hi, > > Here is an attempt to remove the trace.info file. It works well for > me, the reason for it to be an RFC is that I have doubts about the > backward compatibility. > > A file created by perf after his patch is unsupported by previous > version because the size of the headers have increased. That's OK i think in terms of trace.info - trace.info was a temporary hack to begin with. > That said, it's two new fields that have been added in the end of the > headers, and those could be ignored by previous versions if they just > handled the dynamic header size and then ignore the unknow part. The > offsets guarantee the compatibility. Yes, that's how it should work. > But previous versions handle the header size using its static size, > not dynamic, then it's not backward compatible. > > Anyway, I'm not sure exactly how to handle that. That's a bug in the previous version - mind doing a standalone fix for that so we can mark it Cc: stable? Thanks, Ingo