From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754220Ab0EJFta (ORCPT ); Mon, 10 May 2010 01:49:30 -0400 Received: from hera.kernel.org ([140.211.167.34]:59022 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753429Ab0EJFt2 (ORCPT ); Mon, 10 May 2010 01:49:28 -0400 Message-ID: <4BE79E46.2080305@kernel.org> Date: Mon, 10 May 2010 07:48:54 +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: Paul Mackerras CC: Peter Zijlstra , mingo@elte.hu, efault@gmx.de, avi@redhat.com, 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: <1272976724-14312-1-git-send-email-tj@kernel.org> <1272994165.1642.203.camel@laptop> <4BE0FB68.7080403@kernel.org> <1273050400.1642.229.camel@laptop> <4BE13B33.3030709@kernel.org> <1273053073.1642.235.camel@laptop> <4BE1406C.2000400@kernel.org> <20100510052056.GB20793@drongo> In-Reply-To: <20100510052056.GB20793@drongo> 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]); Mon, 10 May 2010 05:49:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 05/10/2010 07:20 AM, Paul Mackerras wrote: > Don't forget where perf_events started out - as a way to count and > record hardware events. So perf_events is very useful even in a > kernel that has no tracing infrastructure configured in at all. Alright, but I don't think it's very relevant to worry about !CONFIG_TRACEPOINTS && CONFIG_PERF_EVENTS case as long as both can be compiled out. TPs are supposed to have very low to almost no runtime overhead and building them into the kernel shouldn't cost all that much either (I hear that it has been improved lately). Sure, perf can be used w/o TPs but I can't see what that configurability buys us. Thanks. -- tejun