From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933599Ab3BLTyE (ORCPT ); Tue, 12 Feb 2013 14:54:04 -0500 Received: from mga11.intel.com ([192.55.52.93]:46146 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933153Ab3BLTyC (ORCPT ); Tue, 12 Feb 2013 14:54:02 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,652,1355126400"; d="scan'208";a="290227366" Message-ID: <511A9DD9.7090805@linux.intel.com> Date: Tue, 12 Feb 2013 11:54:01 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Steven Rostedt CC: LKML , Ingo Molnar , Thomas Gleixner , Frederic Weisbecker , Josh Poimboeuf , Andrew Morton , Vaibhav Nagarnaik Subject: Re: [RFC][PATCH] tracing/syscalls: Have ia32 compat syscalls show raw format References: <1360692087.21867.42.camel@gandalf.local.home> <511A85E8.7030303@linux.intel.com> <1360694555.21867.69.camel@gandalf.local.home> <511A9A64.3040108@linux.intel.com> In-Reply-To: <511A9A64.3040108@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/12/2013 11:39 AM, H. Peter Anvin wrote: > On 02/12/2013 10:42 AM, Steven Rostedt wrote: >> >> And currently the output is just plain broken. This isn't a hack. You >> should have seen my first attempt. Now THAT was a hack! My first attempt >> was extremely intrusive, and required a lot of arch changes. But then I >> realized it was too much, and found that I could do the same thing >> pretty much completely contained within just the tracing code itself. >> >> I know you feel that the syscall tracing is broken/hack/whatever. But it >> exists as of today, and yes, there's lots of users out there depending >> on it. >> > > I am getting extremely frustrated with this cycle: > > 1. "We should have done but we did because was too > hard/required arch changes/..." > 2. "Well, is broken, but people rely on it. We should have done > but now it is too hard/breaks legacy/... so let's do ..." > 3. Lather, rinse, repeat. > > The whole system with trace metadata seems to be broken at the core, > *exactly* because it intercepts at a different place than the one which > has a well-defined ABI and every hack, kluge and patch which doesn't fix > that fundamental design error will just make it worse and just kicks the > can further down the road. > As to why I care: I care about the number of ways we present ABIs to userspace. The current tracing code takes the kernel internal implementation and makes it an ABI -- that ties the hands of kernel developers forever, because we can't know what we break if we redesign it. -hpa