Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752240AbaG1Bih (ORCPT ); Sun, 27 Jul 2014 21:38:37 -0400 Received: from mga11.intel.com ([192.55.52.93]:34153 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751341AbaG1Bif (ORCPT ); Sun, 27 Jul 2014 21:38:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,745,1400050800"; d="scan'208";a="568109198" Date: Mon, 28 Jul 2014 01:36:16 +0800 From: Yuyang Du To: Vincent Guittot Cc: "mingo@redhat.com" , Peter Zijlstra , linux-kernel , Paul Turner , Benjamin Segall , arjan.van.de.ven@intel.com, Len Brown , rafael.j.wysocki@intel.com, alan.cox@intel.com, "Gross, Mark" , "fengguang.wu@intel.com" Subject: Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average tracking Message-ID: <20140727173616.GA22986@intel.com> References: <1405639567-21445-1-git-send-email-yuyang.du@intel.com> <1405639567-21445-3-git-send-email-yuyang.du@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Vincent, On Fri, Jul 18, 2014 at 11:43:00AM +0200, Vincent Guittot wrote: > > @@ -2291,23 +2299,24 @@ static __always_inline int __update_entity_runnable_avg(u64 now, > > delta >>= 10; > > if (!delta) > > return 0; > > - sa->last_runnable_update = now; > > + sa->last_update_time = now; > > > > /* delta_w is the amount already accumulated against our next period */ > > - delta_w = sa->runnable_avg_period % 1024; > > + delta_w = sa->period_contrib; > > if (delta + delta_w >= 1024) { > > - /* period roll-over */ > > decayed = 1; > > > > + /* how much left for next period will start over, we don't know yet */ > > + sa->period_contrib = 0; > > + > > /* > > * Now that we know we're crossing a period boundary, figure > > * out how much from delta we need to complete the current > > * period and accrue it. > > */ > > delta_w = 1024 - delta_w; > > - if (runnable) > > - sa->runnable_avg_sum += delta_w; > > - sa->runnable_avg_period += delta_w; > > + if (w) > > + sa->load_sum += w * delta_w; > > Do you really need to have *w for computing the load_sum ? can't you > only use it when computing the load_avg ? > > sa->load_avg = div_u64(sa->load_sum * w , LOAD_AVG_MAX) > For task, assuming its load.weight does not change much, yes, we can. But in theory, task's load.weight can change, and *w in load_sum can take into that change. For group entity and cfs_rq, its load.weight changes all the time, I don't know how to do it without *w for load_sum. Sorry for my irresponsiveness for last week. I was on vacation and unfortunately failed to connect VPN from where I was. Thanks, Yuyang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/