Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753936Ab2B0EN2 (ORCPT ); Sun, 26 Feb 2012 23:13:28 -0500 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:39031 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753428Ab2B0EN1 (ORCPT ); Sun, 26 Feb 2012 23:13:27 -0500 Date: Mon, 27 Feb 2012 09:42:59 +0530 From: Srivatsa Vaddagiri To: Michael Wang Cc: Peter Zijlstra , Ingo Molnar , LKML Subject: Re: [PATCH v5] sched: Avoid unnecessary work in reweight_entity Message-ID: <20120227041259.GA2331@linux.vnet.ibm.com> Reply-To: Srivatsa Vaddagiri References: <4F308E25.7060101@linux.vnet.ibm.com> <4F31D9B2.5090501@linux.vnet.ibm.com> <4F3D0F41.1010205@linux.vnet.ibm.com> <1329402561.2293.225.camel@twins> <4F3DEDC3.4010004@linux.vnet.ibm.com> <4F3F025B.5010400@linux.vnet.ibm.com> <1329743311.2293.341.camel@twins> <4F4617AB.2080401@linux.vnet.ibm.com> <4F46F105.2000702@linux.vnet.ibm.com> <4F48E882.6090409@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <4F48E882.6090409@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) x-cbid: 12022618-0260-0000-0000-0000009AD6D8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 890 Lines: 36 * Michael Wang [2012-02-25 21:56:18]: > Hi, Peter > > I have collected more testing data, here is the test results: > > Machine: ThinkPad T420 > OS: Ubuntu 11.10 > Benchmark: time make -j14 (build kernel) Is that benchmark run in root (cpu) cgroup? If so, reweight_entity() should not kick in at all. static void update_cfs_shares(struct cfs_rq *cfs_rq) { .. if (!se || throttled_hierarchy(cfs_rq)) return; .. reweight_entity(); } If you want to stress reweight_entity() create several (cpu) cgroups and launch workload like kernbench in each of them .. - vatsa -- 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/