From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753144Ab3LCJGt (ORCPT ); Tue, 3 Dec 2013 04:06:49 -0500 Received: from mail-pd0-f169.google.com ([209.85.192.169]:61922 "EHLO mail-pd0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752231Ab3LCJGl (ORCPT ); Tue, 3 Dec 2013 04:06:41 -0500 From: Alex Shi To: mingo@redhat.com, peterz@infradead.org, morten.rasmussen@arm.com, vincent.guittot@linaro.org, daniel.lezcano@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, alex.shi@linaro.org, jason.low2@hp.com, gregkh@linuxfoundation.org, hanjun.guo@linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/4] sched: remove cpu_load decay Date: Tue, 3 Dec 2013 17:05:52 +0800 Message-Id: <1386061556-28233-1-git-send-email-alex.shi@linaro.org> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 removes the cpu_load decay. 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 8% with this patchset! 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" Daniel tested this patchset on his Core2 2 socket server, the hackbench has no clear regression/improvement. This patchset is also in Fengguang's x86 testing for more than 1 week, and no regression report until now. Fengguang, could I assume there is no regression on Intel platforms? :) The git tree for this patchset at: git@github.com:alexshi/power-scheduling.git no-load-idx -- Thanks Alex