Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758621AbaDXR3n (ORCPT ); Thu, 24 Apr 2014 13:29:43 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:47304 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757055AbaDXR3m (ORCPT ); Thu, 24 Apr 2014 13:29:42 -0400 Date: Thu, 24 Apr 2014 19:29:33 +0200 From: Peter Zijlstra To: Jason Low Cc: Preeti U Murthy , mingo@kernel.org, linux-kernel@vger.kernel.org, daniel.lezcano@linaro.org, alex.shi@linaro.org, efault@gmx.de, vincent.guittot@linaro.org, morten.rasmussen@arm.com, aswin@hp.com, chegu_vinod@hp.com Subject: Re: [PATCH 1/3] sched, balancing: Update rq->max_idle_balance_cost whenever newidle balance is attempted Message-ID: <20140424172933.GU13658@twins.programming.kicks-ass.net> References: <1398303035-18255-1-git-send-email-jason.low2@hp.com> <1398303035-18255-2-git-send-email-jason.low2@hp.com> <5358E417.8090503@linux.vnet.ibm.com> <20140424120415.GS11096@twins.programming.kicks-ass.net> <20140424124438.GT13658@twins.programming.kicks-ass.net> <1398358417.3509.11.camel@j-VirtualBox> <20140424171453.GZ11096@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140424171453.GZ11096@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 24, 2014 at 07:14:53PM +0200, Peter Zijlstra wrote: > On Thu, Apr 24, 2014 at 09:53:37AM -0700, Jason Low wrote: > > > > So I thought that the original rationale (commit 1bd77f2d) behind > > updating rq->next_balance in idle_balance() is that, if we are going > > idle (!pulled_task), we want to ensure that the next_balance gets > > calculated without the busy_factor. > > > > If the rq is busy, then rq->next_balance gets updated based on > > sd->interval * busy_factor. However, when the rq goes from "busy" > > to idle, rq->next_balance might still have been calculated under > > the assumption that the rq is busy. Thus, if we are going idle, we > > would then properly update next_balance without the busy factor > > if we update when !pulled_task. > > > > Its late here and I'm confused! > > So the for_each_domain() loop calculates a new next_balance based on > ->balance_interval (which has that busy_factor on, right). Not right, ->balance_interval is the base interval. rebalance_domains() doesn't update it. -- 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/