From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754303Ab2DWIeM (ORCPT ); Mon, 23 Apr 2012 04:34:12 -0400 Received: from casper.infradead.org ([85.118.1.10]:48426 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754201Ab2DWIeK convert rfc822-to-8bit (ORCPT ); Mon, 23 Apr 2012 04:34:10 -0400 Message-ID: <1335170023.28150.97.camel@twins> Subject: Re: [PATCH 12/16] rtmutex: turn the plist into an rb-tree. From: Peter Zijlstra To: Steven Rostedt Cc: Juri Lelli , tglx@linutronix.de, mingo@redhat.com, oleg@redhat.com, fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch, linux-kernel@vger.kernel.org, claudio@evidence.eu.com, michael@amarulasolutions.com, fchecconi@gmail.com, tommaso.cucinotta@sssup.it, nicola.manica@disi.unitn.it, luca.abeni@unitn.it, dhaval.giani@gmail.com, hgu1972@gmail.com, paulmck@linux.vnet.ibm.com, raistlin@linux.it, insop.song@ericsson.com, liming.wang@windriver.com Date: Mon, 23 Apr 2012 10:33:43 +0200 In-Reply-To: <1334178715.23924.308.camel@gandalf.stny.rr.com> References: <1333696481-3433-1-git-send-email-juri.lelli@gmail.com> <1333696481-3433-13-git-send-email-juri.lelli@gmail.com> <1334178715.23924.308.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-04-11 at 17:11 -0400, Steven Rostedt wrote: > > I have to ask. Why not just add a rbtree with a plist? That is, add all > deadline tasks to the rbtree and all others to the plist. As plist has a > O(1) operation, and rbtree does not. We are making all RT tasks suffer > the overhead of the rbtree. You always love to add complexity to stuff before making it work, don't you ;-) I'm not quite convinced the plist stuff is _that_ much faster, anyway, its all a stop-gap measure until we can do proper BWI which would wipe all this code anyway.