From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753411Ab0EFHLr (ORCPT ); Thu, 6 May 2010 03:11:47 -0400 Received: from hera.kernel.org ([140.211.167.34]:54057 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264Ab0EFHLo (ORCPT ); Thu, 6 May 2010 03:11:44 -0400 Message-ID: <4BE26B96.4040007@kernel.org> Date: Thu, 06 May 2010 09:11:18 +0200 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 MIME-Version: 1.0 To: Ingo Molnar CC: Frederic Weisbecker , Peter Zijlstra , efault@gmx.de, avi@redhat.com, paulus@samba.org, acme@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCHSET] sched,perf: unify tracers in sched and move perf on top of TP References: <1273050400.1642.229.camel@laptop> <4BE13B33.3030709@kernel.org> <1273053073.1642.235.camel@laptop> <4BE1406C.2000400@kernel.org> <1273059488.1642.245.camel@laptop> <4BE1648B.1080709@kernel.org> <20100505165532.GC14323@elte.hu> <1273083173.1642.250.camel@laptop> <1273083396.1642.251.camel@laptop> <20100505183000.GF6320@nowhere> <20100506062855.GD1172@elte.hu> In-Reply-To: <20100506062855.GD1172@elte.hu> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Thu, 06 May 2010 07:11:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 05/06/2010 08:28 AM, Ingo Molnar wrote: > ( They are also under intense optimization - the jump-tracepoints patch makes > them probably even cheaper than preempt notifiers, in the off case. ) I mostly agree on other points but TPs and sched_notifiers are inherently different in how they are enabled/disabled. sched_notifiers are enabled/disabled per-task and at least w/ cmwq, there will always be some tasks with active sched_notifiers so code level optimizations aren't really useful. Thanks. -- tejun