From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 07 Dec 2002 00:19:30 +0100 (MET) Received: from onda.linux-mips.net ([IPv6:::ffff:192.168.169.2]:38828 "EHLO dea.linux-mips.net") by ralf.linux-mips.org with ESMTP id ; Sat, 7 Dec 2002 00:19:21 +0100 Received: (from ralf@localhost) by dea.linux-mips.net (8.11.6/8.11.6) id gB6NHVD13388; Sat, 7 Dec 2002 00:17:31 +0100 Date: Sat, 7 Dec 2002 00:17:31 +0100 From: Ralf Baechle To: Dominic Sweetman Cc: Thiemo Seufer , "Maciej W. Rozycki" , Carsten Langgaard , "Kevin D. Kissell" , linux-mips@linux-mips.org Subject: Re: Latest sources from CVS. Message-ID: <20021207001731.D12968@linux-mips.org> References: <20021206135110.GD23743@rembrandt.csv.ica.uni-stuttgart.de> <20021206164558.GH23743@rembrandt.csv.ica.uni-stuttgart.de> <20021206180241.A7492@linux-mips.org> <15856.59886.661994.493446@gladsmuir.algor.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <15856.59886.661994.493446@gladsmuir.algor.co.uk>; from dom@algor.co.uk on Fri, Dec 06, 2002 at 06:18:22PM +0000 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 818 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Fri, Dec 06, 2002 at 06:18:22PM +0000, Dominic Sweetman wrote: > > The first kernel was built as 64-bit ELF using 64-bit pointer and everything > > 64-bit. The second kernel was built using the -Wa,-32 trick. That's over > > 12% of bloat for full 64-bitiness which brings zero gain. > > Percentages are dangerous things. This is 220Kbytes of memory, which > currently represents an investment of about $0.05. There may be > embedded linux applications which care about 5c cost, but they > probably won't use any variety of 64 bits... I'd worry less if that was just 220kB of unused memory wasted. But it's actually inflated code, it's wasted i-cache and cycles. 220kB translates to alost 7 times the size of today's typical 32kB i-cache. Even if Thiemo was right this trick is probably the biggest micro- optimization of the decade ... Ralf