Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754474AbcJIDjb (ORCPT ); Sat, 8 Oct 2016 23:39:31 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36173 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753439AbcJIDj3 (ORCPT ); Sat, 8 Oct 2016 23:39:29 -0400 MIME-Version: 1.0 In-Reply-To: <20160928193731.GD16071@codeblueprint.co.uk> References: <20160923115808.2330-1-matt@codeblueprint.co.uk> <20160928101422.GR5016@twins.programming.kicks-ass.net> <20160928193731.GD16071@codeblueprint.co.uk> From: Wanpeng Li Date: Sun, 9 Oct 2016 11:39:27 +0800 Message-ID: Subject: Re: [PATCH] sched/fair: Do not decay new task load on first enqueue To: Matt Fleming Cc: Peter Zijlstra , Ingo Molnar , "linux-kernel@vger.kernel.org" , Mike Galbraith , Yuyang Du , Vincent Guittot , Dietmar Eggemann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 870 Lines: 21 2016-09-29 3:37 GMT+08:00 Matt Fleming : > On Wed, 28 Sep, at 12:14:22PM, Peter Zijlstra wrote: >> >> Which suggests we do something like the below (not compile tested or >> anything, also I ran out of tea again). > > I'm away on FTO right now. I can test this when I return on Friday. > > Funnily enough, I now remember that I already sent a fix for the > missing update_rq_clock() in post_init_entity_util_avg(), but didn't > apply it when chasing this hackbench regression (oops), > > https://lkml.kernel.org/r/20160921133813.31976-3-matt@codeblueprint.co.uk The difference between this patch and Peterz's is your patch have a delta since activate_task()->enqueue_task() does do update_rq_clock(), so why don't have the delta will cause low cpu machines (4 or 8) to regress against your another reply in this thread? Regards, Wanpeng Li