Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 6 Feb 2003 16:24:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 6 Feb 2003 16:24:42 -0500 Received: from [81.2.122.30] ([81.2.122.30]:41991 "EHLO darkstar.example.net") by vger.kernel.org with ESMTP id ; Thu, 6 Feb 2003 16:24:41 -0500 From: John Bradford Message-Id: <200302062132.h16LWtTn002739@darkstar.example.net> Subject: Re: gcc -O2 vs gcc -Os performance To: mbligh@aracnet.com (Martin J. Bligh) Date: Thu, 6 Feb 2003 21:32:55 +0000 (GMT) Cc: alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org, lse-tech@lists.sourceforge.net In-Reply-To: <263740000.1044563891@[10.10.2.4]> from "Martin J. Bligh" at Feb 06, 2003 12:38:11 PM X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 26 > >> All done with gcc-2.95.4 (Debian Woody). These machines (16x NUMA-Q) have > >> 700MHz P3 Xeons with 2Mb L2 cache ... -Os might fare better on celeron > >> with a puny cache if someone wants to try that out > > > > gcc 3.2 is a lot smarter about -Os and it makes a very big size > > difference according to the numbers the from the ACPI guys. > > > > Im not sure testing with a gcc from the last millenium is useful 8) > > Still no use. > /me throws gcc-3.2 in the trash can. What submodel options are you using? If you're compiling with -march=i386, I wouldn't expect -Os to have much effect. Note that, of all architectures, GCC is almost certainly most efficient on IA-32. Although I haven't done any benchmarks against other compilers on $arch!=IA32, the ones I've seen claim that the native compiler generates much better code. John. - 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/