From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755538Ab3KVMNo (ORCPT ); Fri, 22 Nov 2013 07:13:44 -0500 Received: from mail-ee0-f51.google.com ([74.125.83.51]:62433 "EHLO mail-ee0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755202Ab3KVMNm (ORCPT ); Fri, 22 Nov 2013 07:13:42 -0500 Message-ID: <528F4A78.1080505@linaro.org> Date: Fri, 22 Nov 2013 13:13:44 +0100 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Alex Shi , mingo@redhat.com, peterz@infradead.org, morten.rasmussen@arm.com, vincent.guittot@linaro.org, fweisbec@gmail.com, linux@arm.linux.org.uk, tony.luck@intel.com, fenghua.yu@intel.com, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, pjt@google.com, fengguang.wu@intel.com CC: james.hogan@imgtec.com, jason.low2@hp.com, gregkh@linuxfoundation.org, hanjun.guo@linaro.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/4] sched: remove cpu_load decay. References: <1385102235-25664-1-git-send-email-alex.shi@linaro.org> In-Reply-To: <1385102235-25664-1-git-send-email-alex.shi@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/22/2013 07:37 AM, Alex Shi wrote: > The cpu_load decays on time according past cpu load of rq. New sched_avg decays on tasks' load of time. Now we has 2 kind decay for cpu_load. That is a kind of redundancy. And increase the system load in sched_tick etc. > > This patch trying to remove the cpu_load decay. And fixed a nohz_full bug by the way. > > There are 5 load_idx used for cpu_load in sched_domain. busy_idx and idle_idx are not zero usually, but newidle_idx, wake_idx and forkexec_idx are all zero on every arch. A shortcut to remove cpu_Load decay in the first patch. just one line patch for this change. :) > > I have tested the patchset on my pandaES board, 2 cores ARM Cortex A9. > hackbench thread/pipe performance increased nearly 10% with this patchset! That do surprise me! > > latest kernel 527d1511310a89 + this patchset > hackbench -T -g 10 -f 40 > 23.25" 21.7" > 23.16" 19.99" > 24.24" 21.53" > hackbench -p -g 10 -f 40 > 26.52" 22.48" > 23.89" 24.00" > 25.65" 23.06" > hackbench -P -g 10 -f 40 > 20.14" 19.37" > 19.96" 19.76" > 21.76" 21.54" > > The git tree for this patchset at: > git@github.com:alexshi/power-scheduling.git no-load-idx > Since Fengguang had included this tree into his kernel testing system. and I haven't get a regression report until now. I suppose it is fine for x86 system. > > But anyway, since the scheduler change will effect all archs. and hackbench is only benchmark I found now for this patchset. I'd like to see more testing and talking on this patchset. Hi Alex, I tried on my Xeon server (2 x 4 cores) your patchset and got the following result: kernel a5d6e63323fe7799eb0e6 / + patchset hackbench -T -s 4096 -l 1000 -g 10 -f 40 27.604 38.556 27.397 38.694 26.695 38.647 25.975 38.528 29.586 38.553 25.956 38.331 27.895 38.472 26.874 38.608 26.836 38.341 28.064 38.626 hackbench -p -s 4096 -l 1000 -g 10 -f 40 34.502 35.489 34.551 35.389 34.027 35.664 34.343 35.418 34.570 35.423 34.386 35.466 34.387 35.486 33.869 35.212 34.600 35.465 34.155 35.235 hackbench -P -s 4096 -l 1000 -g 10 -f 40 39.170 38.794 39.108 38.662 39.056 38.946 39.120 38.668 38.896 38.865 39.109 38.803 39.020 38.946 39.099 38.844 38.820 38.872 38.923 39.337 -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog