Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754321AbXJ3OOW (ORCPT ); Tue, 30 Oct 2007 10:14:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752855AbXJ3OOO (ORCPT ); Tue, 30 Oct 2007 10:14:14 -0400 Received: from ftp.linux-mips.org ([194.74.144.162]:48148 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752498AbXJ3OON (ORCPT ); Tue, 30 Oct 2007 10:14:13 -0400 Date: Tue, 30 Oct 2007 14:14:01 +0000 From: Ralf Baechle To: Matthew Wilcox Cc: Kumar Gala , Kyle McMartin , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Only show RESOURCES_64BIT on relevant architectures Message-ID: <20071030141401.GB27615@linux-mips.org> References: <20071028201549.GA23138@fattire.cabal.ca> <20071030024801.GA19417@linux-mips.org> <20071030083719.GJ32359@parisc-linux.org> <20071030114221.GA24392@linux-mips.org> <20071030121315.GK32359@parisc-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071030121315.GK32359@parisc-linux.org> User-Agent: Mutt/1.5.14 (2007-02-12) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1490 Lines: 32 On Tue, Oct 30, 2007 at 06:13:16AM -0600, Matthew Wilcox wrote: > > On Tue, Oct 30, 2007 at 02:37:19AM -0600, Matthew Wilcox wrote: > > > On Mon, Oct 29, 2007 at 10:03:16PM -0500, Kumar Gala wrote: > > > > same HW platform that you want to run with just 32-bit phys (for > > > > performance). > > > > > > Have you measured what the performance difference is? > > > > So that's 5668, 256 bytes data and 128 bytes of bss for a total of 6052 > > bytes. Not a whole lot but I still fear some users on the most > > claustrophobic systems will mind. > > Oh, sure, I'm not saying I thought there would be no size difference; I > was just bemused at the suggestion there was a performance difference. > > Unless "won't fit in ROM any more" is considered a performance problem ;-) Linux has traditionally had a paranoid fear of 64-bit datatypes just because GCC doesn't generate terribly efficient code for i386. I think that may be the primary reason why CONFIG_RESOURCES_64BIT ever became a build option. I doubt resource_size_t is being used in any critical path so the bloat factor will matter much more than the performance difference it makes. Unless you're terribly impatient waiting for your PCI bus to complete scan or so ;-) Ralf - 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/