From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756646AbcANTn0 (ORCPT ); Thu, 14 Jan 2016 14:43:26 -0500 Received: from casper.infradead.org ([85.118.1.10]:42413 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756426AbcANTnZ (ORCPT ); Thu, 14 Jan 2016 14:43:25 -0500 Date: Thu, 14 Jan 2016 20:43:23 +0100 From: Peter Zijlstra To: Luca Abeni Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Juri Lelli Subject: Re: [RFC 4/8] Improve the tracking of active utilisation Message-ID: <20160114194323.GC6357@twins.programming.kicks-ass.net> References: <1452785094-3086-1-git-send-email-luca.abeni@unitn.it> <1452785094-3086-5-git-send-email-luca.abeni@unitn.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452785094-3086-5-git-send-email-luca.abeni@unitn.it> 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, Jan 14, 2016 at 04:24:49PM +0100, Luca Abeni wrote: > This patch implements a more theoretically sound algorithm for > thracking the active utilisation: instead of decreasing it when a > task blocks, use a timer (the "inactive timer", named after the > "Inactive" task state of the GRUB algorithm) to decrease the > active utilisaation at the so called "0-lag time". See also the large-ish comment in __setparam_dl(). If we go do proper 0-lag, as GRUB requires, then we might as well use it for that. But we need to sort the issue of the task exiting with an armed timer. The solution suggested there is keeping a task reference with the timer.