From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932313AbcLHQ5G (ORCPT ); Thu, 8 Dec 2016 11:57:06 -0500 Received: from mail-wj0-f175.google.com ([209.85.210.175]:36411 "EHLO mail-wj0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932109AbcLHQ5E (ORCPT ); Thu, 8 Dec 2016 11:57:04 -0500 From: Vincent Guittot To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, matt@codeblueprint.co.uk, Morten.Rasmussen@arm.com Cc: dietmar.eggemann@arm.com, kernellwp@gmail.com, yuyang.du@intel.comc, umgwanakikbuti@gmail.com, Vincent Guittot Subject: [PATCH 0/2 v3] sched: improve spread of tasks during fork Date: Thu, 8 Dec 2016 17:56:52 +0100 Message-Id: <1481216215-24651-1-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Performance regression has been raised by Matt Fleming for fork intensive bench like hackbench [1] The patch 1/2 skips the spare_capacity test for fork task because the utilization has not beed init yet. The patch 2/2 takes into account load_avg for selecting CPU when runnable_load of CPUs are close Tests done by Matt Fleming show perf improvements with the patchset : [2] [3] Changes since v2: - renamed no_spare label to skip_spare - changed load_avg test condition to prefer local cpu when load are similar - added explanation for using absoluate margin instead of scale factor when comparing runnable_load [1] https://lkml.org/lkml/2016/10/18/206 [2] https://lkml.org/lkml/2016/12/8/260 [3] https://lkml.org/lkml/2016/12/8/260 Vincent Guittot (2): sched: fix find_idlest_group for fork sched: use load_avg for selecting idlest group kernel/sched/fair.c | 54 +++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 44 insertions(+), 10 deletions(-) -- 2.7.4