Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754741Ab3ILT2y (ORCPT ); Thu, 12 Sep 2013 15:28:54 -0400 Received: from mail-qc0-f170.google.com ([209.85.216.170]:61321 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752753Ab3ILT2x (ORCPT ); Thu, 12 Sep 2013 15:28:53 -0400 Date: Thu, 12 Sep 2013 15:35:52 -0400 (EDT) From: Vince Weaver To: Ingo Molnar cc: Andi Kleen , Andi Kleen , acme@infradead.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Stephane Eranian , torvalds@linux-foundation.org, trinity@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , =?ISO-8859-15?Q?Fr=E9d=E9ric_Weisbecker?= , Jiri Olsa , Namhyung Kim , Greg Kroah-Hartman Subject: Re: [PATCH 1/2] tools, perf: Add a precise event qualifier v2 In-Reply-To: <20130912165733.GA23698@gmail.com> Message-ID: References: <1374501138-13496-1-git-send-email-andi@firstfloor.org> <20130723060108.GA18396@tassilo.jf.intel.com> <20130723225150.GT6123@two.firstfloor.org> <20130912165733.GA23698@gmail.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1868 Lines: 55 On Thu, 12 Sep 2013, Ingo Molnar wrote: > * Andi Kleen wrote: > > > On Tue, Jul 23, 2013 at 05:27:43PM -0400, Vince Weaver wrote: > > > > > > I hate having to justify why breaking the ABI is unacceptable. > > > > Well it's a testing ABI, so we can do changes to it. > > > > I hope you're not suggesting that perf cannot be extended anymore. > > It obviously should remain extensible, limiting it to 'config' is rather > stupid. If a parser sees something it cannot parse it should ignore that > event. Well Documentation/ABI/testing/sysfs-bus-event_source-devices-events implies that you won't find field names that aren't in a format file, and Documentation/ABI/testing/sysfs-bus-event_source-devices-format specifies that only "config" fields will appear there. So if this will be changing you might want to update the documentation, or just remove it altogether because it is getting increasingly inaccurate. I've tried getting this documentation updated ( https://lkml.org/lkml/2013/7/25/2 ) but the patches have been ignored. In any case, I notice perf also uses the "open" syscall, so I look forward to your eventual creation of /sys/bus/open/file_permissions/* $ cat /sys/bus/open/file_permissions/write flags=0101,mode=0666 Because what every system call needs is some sort of tree under sysfs exporting various common settings in unswappable kernel memory that require a complex LEX/YACC parser to interpret. That's much simpler than using a library, or having a user looking things up in a manpage and placing a few comments in their code. Vince -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/