From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1954754AbdDYVIV (ORCPT ); Tue, 25 Apr 2017 17:08:21 -0400 Received: from mail-it0-f50.google.com ([209.85.214.50]:37187 "EHLO mail-it0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993645AbdDYVIN (ORCPT ); Tue, 25 Apr 2017 17:08:13 -0400 Date: Tue, 25 Apr 2017 14:08:10 -0700 From: Tejun Heo To: Vincent Guittot Cc: Ingo Molnar , Peter Zijlstra , linux-kernel , Linus Torvalds , Mike Galbraith , Paul Turner , Chris Mason , kernel-team@fb.com Subject: Re: [PATCH 2/2] sched/fair: Always propagate runnable_load_avg Message-ID: <20170425210810.GB20255@wtj.duckdns.org> References: <20170424201344.GA14169@wtj.duckdns.org> <20170424201444.GC14169@wtj.duckdns.org> <20170425184941.GB15593@wtj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170425184941.GB15593@wtj.duckdns.org> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 25, 2017 at 11:49:41AM -0700, Tejun Heo wrote: > > I have run a quick test with your patches and schbench on my platform. > > I haven't been able to reproduce your regression but my platform is > > quite different from yours (only 8 cores without SMT) > > But most importantly, the parent cfs_rq->runnable_load_avg never > > reaches 0 (or almost 0) when it is idle. Instead, it still has a > > runnable_load_avg (this is not due to rounding computation) whereas > > runnable_load_avg should be 0 > > Heh, let me try that out. Probably a silly mistake somewhere. This is from the follow-up patch. I was confused. Because we don't propagate decays, we still should decay the runnable_load_avg; otherwise, we end up accumulating errors in the counter. I'll drop the last patch. Thanks. -- tejun