From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760621AbaEMKDm (ORCPT ); Tue, 13 May 2014 06:03:42 -0400 Received: from casper.infradead.org ([85.118.1.10]:40417 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759837AbaEMKDj (ORCPT ); Tue, 13 May 2014 06:03:39 -0400 Date: Tue, 13 May 2014 12:03:33 +0200 From: Peter Zijlstra To: Dongsheng Yang Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org, Steven Rostedt Subject: Re: perf,tools: Remove usage of trace_sched_wakeup(.success) Message-ID: <20140513100333.GW30445@twins.programming.kicks-ass.net> References: <20140512181946.GG13467@laptop.programming.kicks-ass.net> <20140513072208.GB7980@gmail.com> <5371BCF8.7030708@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="cs2w6Z3FJD+b2LjO" Content-Disposition: inline In-Reply-To: <5371BCF8.7030708@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --cs2w6Z3FJD+b2LjO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 13, 2014 at 03:34:32PM +0900, Dongsheng Yang wrote: > On 05/13/2014 04:22 PM, Ingo Molnar wrote: > >* Peter Zijlstra wrote: > > > >>trace_sched_wakeup(.success) is a dead argument and has been for ages, > >Always 0, or random value? >=20 > Hi Ingo, >=20 > It is always 1 currently. >=20 > Peter believe that .success is not useful and I pointed that perf sched > latency > is using it now. Then he post this patch to remove the usage here. >=20 > Please go to the following link for more about this issue. It is _not_ usable. You're proposing to abuse the existing parameter. A wakeup doing an enqueue or not has nothing _WHAT_SO_EVER_ to do with success. Now what I think you wanted to do is make it easier to match trace_sched_switch() statements with trace_sched_wakeup() statements. And since you only get the trace_sched_switch() on dequeue, you want to know which trace_sched_wakeup() calls did an enqueue. But that's completely and utterly unrelated to success. --cs2w6Z3FJD+b2LjO Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTce31AAoJEHZH4aRLwOS6cngP/iHaM7Y0NhcYARQKUAbJ3HwI JVEXitZIa8By++QIkdVgD8PXYH/uSi4ChNyBbSX4c4QX8a6CBw8YdZGx2nH9Egy6 cmJ3bAH3ZOlOqS3pxFteyGVbPH1odFfLqct3MVurkdBkfy4XBHaLGgFH4R9Gku6t YlnRb8VW4Tr4X5ACLBcCZsQoUYA48ZDufva4y/0BtvVnZ+EdzncESKxtE9bgnvot ulDKQ8VzG+jnfbwUoAIOzMXHv3bYl5oJcA5AiAxxYCymjTkQcLY/o/yqMiOyazK7 aJEeNLLp/BtvyYiOk4BTLzXDMroQNAh5teKw+Z3PwZcYh6kJH32805S+aAp8Bfzn b9YI95JugrPCPm5I23wa550RZOhWWynVJgIZ7Xgr60cCgP1mBS+th7WPwE0KZwT/ crwnWOJoA3qpWoKYSLGr4C6d4ATV+jFj9mUst9JsLP8aletg8h/Dve4Q2SbYSGgc /gIKYysRvO80S8RwXMUrmSG3pU9gVEx2cXs7gvephiYMWa+zNWtLG1gMpY1pBfN1 FGdn1O/4l2uVe7be1rAy5w61PIjpOZwHItIF/6cHMJMLuN7wWNB55W5wNNVo4/BL Xsw/+FX1ZNNU70slpuktAIm5de0qLQeuDA08RbNj0G0OsP5yEJL6sp3doxVnIWyj dBN4LcFRI60PWvzhcElJ =9Jgy -----END PGP SIGNATURE----- --cs2w6Z3FJD+b2LjO--