From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754308AbaEHQ7b (ORCPT ); Thu, 8 May 2014 12:59:31 -0400 Received: from g4t3426.houston.hp.com ([15.201.208.54]:58554 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752485AbaEHQ7a (ORCPT ); Thu, 8 May 2014 12:59:30 -0400 Message-ID: <1399568364.2030.9.camel@j-VirtualBox> Subject: Re: [PATCH 2/2] sched: Fix next_balance logic in rebalance_domains() and idle_balance() From: Jason Low To: mingo@kernel.org, peterz@infradead.org, jason.low2@hp.com Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, daniel.lezcano@linaro.org, alex.shi@linaro.org, preeti@linux.vnet.ibm.com, efault@gmx.de, vincent.guittot@linaro.org, morten.rasmussen@arm.com, aswin@hp.com Date: Thu, 08 May 2014 09:59:24 -0700 In-Reply-To: <1398725155-7591-3-git-send-email-jason.low2@hp.com> References: <1398725155-7591-1-git-send-email-jason.low2@hp.com> <1398725155-7591-3-git-send-email-jason.low2@hp.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-04-28 at 15:45 -0700, Jason Low wrote: > Currently, in idle_balance(), we update rq->next_balance when we pull_tasks. > However, it is also important to update this in the !pulled_tasks case too. > > When the CPU is "busy" (the CPU isn't idle), rq->next_balance gets computed > using sd->busy_factor (so we increase the balance interval when the CPU is > busy). However, when the CPU goes idle, rq->next_balance could still be set > to a large value that was computed with the sd->busy_factor. > > Thus, we need to also update rq->next_balance in idle_balance() in the cases > where !pulled_tasks too, so that rq->next_balance gets updated without taking > the busy_factor into account when the CPU is about to go idle. > > This patch makes rq->next_balance get updated independently of whether or > not we pulled_task. Also, we add logic to ensure that we always traverse > at least 1 of the sched domains to get a proper next_balance value for > updating rq->next_balance. > > Additionally, since load_balance() modifies the sd->balance_interval, we > need to re-obtain the sched domain's interval after the call to > load_balance() in rebalance_domains() before we update rq->next_balance. > > This patch adds and uses 2 new helper functions, update_next_balance() and > get_sd_balance_interval() to update next_balance and obtain the sched > domain's balance_interval. Hi Peter, I noticed that patch 1 is in tip, but not this patch 2. I was wondering what the current status with this [PATCH 2/2] is at the moment.