From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965529AbXCLK63 (ORCPT ); Mon, 12 Mar 2007 06:58:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965538AbXCLK63 (ORCPT ); Mon, 12 Mar 2007 06:58:29 -0400 Received: from one.firstfloor.org ([213.235.205.2]:55628 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965529AbXCLK62 (ORCPT ); Mon, 12 Mar 2007 06:58:28 -0400 Date: Mon, 12 Mar 2007 11:58:26 +0100 From: Andi Kleen To: Thomas Gleixner Cc: Andi Kleen , Ingo Molnar , Roland McGrath , akpm@linux-foundation.org, mm-commits@vger.kernel.org, npiggin@suse.de, drepper@redhat.com, oleg@tv-sign.ru, sebastien.dugue@bull.net, linux-kernel@vger.kernel.org Subject: Re: [patch] change futex_wait() to hrtimers Message-ID: <20070312105826.GB11864@one.firstfloor.org> References: <200703110814.l2B8EaI1007615@shell0.pdx.osdl.net> <20070312011259.3834A1801C4@magilla.sf.frob.com> <20070312091006.GF21024@elte.hu> <1173697220.13341.84.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1173697220.13341.84.camel@localhost.localdomain> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 12, 2007 at 12:00:20PM +0100, Thomas Gleixner wrote: > On Mon, 2007-03-12 at 12:27 +0100, Andi Kleen wrote: > > Ingo Molnar writes: > > > > > > the only correct approach is the use of hrtimers, and a patch exists for > > > that - see below. This has been included in -rt for quite some time. > > > > But isn't that bad for power management? You'll likely get more > > idle wakeups, won't you? > > Why so ? It comes more precise, but only once. When it's clustered around the jiffies interval then wakeups from multiple processes will be somewhat batched. With a precise wakeup you'll get wakeups all over the jiffies period, won't you? -Andi