From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754474Ab1GOS7l (ORCPT ); Fri, 15 Jul 2011 14:59:41 -0400 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:59533 "EHLO out4.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752258Ab1GOS7j (ORCPT ); Fri, 15 Jul 2011 14:59:39 -0400 X-Sasl-enc: 0kI6Zme5SHYhhwXpQB1roESPLVLYVlH7fVdIrTBDUW1J 1310756379 Date: Fri, 15 Jul 2011 15:59:36 -0300 From: Henrique de Moraes Holschuh To: Richard Kennedy Cc: Peter Zijlstra , Ingo Molnar , lkml Subject: Re: [PATCH] sched: reorder root_domain to remove 64 bit alignment padding Message-ID: <20110715185936.GA22168@khazad-dum.debian.net> References: <1310726492.1977.5.camel@castor.rsk> <1310726660.2586.313.camel@twins> <1310728994.1977.15.camel@castor.rsk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1310728994.1977.15.camel@castor.rsk> X-GPG-Fingerprint: 1024D/1CDB0FE3 5422 5C61 F6B7 06FB 7E04 3738 EE25 DE3F 1CDB 0FE3 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 15 Jul 2011, Richard Kennedy wrote: > On Fri, 2011-07-15 at 12:44 +0200, Peter Zijlstra wrote: > > On Fri, 2011-07-15 at 11:41 +0100, Richard Kennedy wrote: > > > Reorder root_domain to remove 8 bytes of alignment padding on 64 bit > > > builds, this shrinks the size from 1736 to 1728 bytes, therefore using > > > one fewer cachelines. > > > > depends a bit on how insane struct cpupri is, but yeah, good compaction. > > Thanks! > > Thanks Peter, > > argh -- I hadn't spotted that cpupri used NR_CPUS and was so variable in > size. I guess there won't be much benefit then, as the distros seem to > always set NR_CPUS to some insanely huge value ;) There will be, for those who _do_ care about performance (and thus have sane NR_CPUS for their boxes, among other things). Please don't be discouraged over this. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh