From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753442Ab1F2DXB (ORCPT ); Tue, 28 Jun 2011 23:23:01 -0400 Received: from mga02.intel.com ([134.134.136.20]:34590 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289Ab1F2DWy (ORCPT ); Tue, 28 Jun 2011 23:22:54 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.65,441,1304319600"; d="scan'208";a="21325863" Subject: Re: power increase issue on light load From: "Alex,Shi" To: Nikhil Rao Cc: Peter Zijlstra , "mingo@elte.hu" , "Chen, Tim C" , "Li, Shaohua" , "linux-kernel@vger.kernel.org" , "Brown, Len" In-Reply-To: References: <1308797024.23204.95.camel@debian> <1308819748.1022.69.camel@twins> <1308876099.23204.124.camel@debian> <1309219329.14604.11.camel@debian> <1309273180.6701.213.camel@twins> Content-Type: text/plain; charset="UTF-8" Date: Wed, 29 Jun 2011 11:22:44 +0800 Message-ID: <1309317764.14604.92.camel@debian> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Looking at the schedstat data Alex posted: > - Distribution of load balances across cores looks about the same. > - Load balancer does more idle balances on 3.0-rc4 as compared to > 2.6.39 on SMT and NUMA domains. Busy and newidle balances are a mixed > bag. > - I see far fewer affine wakeups on 3.0-rc4 as compared to 2.6.39. > About half as many affine wakeups on SMT and about a quarter as many > on NUMA. > > I'm investigating the impact of the load resolution patchset on > effective load and wake affine calculations. This seems to be the most > obvious difference from the schedstat data. > > Alex -- I have a couple of questions about your test setup and results. > - What is the impact on throughput of these benchmarks? both on bltk-office and light load specpower, 10%/20%/30% load, the throughput almost have no change on my NHM-EP server and t410 laptop. > - Would it be possible to get a "perf sched" trace on these two kernels? I will run the testing again and give you data later. but I didn't find more useful data in 'perf record -e sched*'. > - I'm assuming the three sched domains are SMT, MC and NUMA. Is that > right? Do you have any powersavings balance or special sched domain > flags enabled? Yes, and the sched_mc_power_savings and sched_smt_power_savings were both set. the NHM-EP domain like below: CPU15 attaching sched-domain: domain 0: span 7,15 level SIBLING groups: 15 (cpu_power = 589) 7 (cpu_power = 589) domain 1: span 1,3,5,7,9,11,13,15 level MC groups: 7,15 (cpu_power = 1178) 1,9 (cpu_power = 1178) 3,11 (cpu_power = 1178) 5,13 (cpu_power = 1178) domain 2: span 0-15 level NODE groups: 1,3,5,7,9,11,13,15 (cpu_power = 4712) 0,2,4,6,8,10,12,14 (cpu_power = 4712) > - Are you using group scheduling? If so, what does your setup look like? I enabled the FAIR group default. But I have tried to disable it. the problem is same. so, it isn't related to group. > > -Thanks, > Nikhil