From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261723AbTJRRK2 (ORCPT ); Sat, 18 Oct 2003 13:10:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261724AbTJRRK2 (ORCPT ); Sat, 18 Oct 2003 13:10:28 -0400 Received: from natsmtp00.rzone.de ([81.169.145.165]:30436 "EHLO natsmtp00.webmailer.de") by vger.kernel.org with ESMTP id S261723AbTJRRK0 (ORCPT ); Sat, 18 Oct 2003 13:10:26 -0400 Message-ID: <3F9173FE.5080308@softhome.net> Date: Sat, 18 Oct 2003 19:10:22 +0200 From: "Ihar 'Philips' Filipau" Organization: Home Sweet Home User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20030927 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Martin J. Bligh" CC: Linux Kernel Mailing List Subject: Re: [2.6 patch] add a config option for -Os compilation References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Martin J. Bligh wrote: > If you have a puny 128K L2 cache, it might help, [ I accept this as a flame-bait. ] Can you be little bit less ignorant? Eh? Please. I beg you. Linux is used not only by you, and not only on huge NUMA boxes with huge caches to hide stupid design flaws. (can't wait when clusters of hand-helds connected over bluetooth will wipe out mainframe market :))) My system has 16K L1 cache. Only L1. And what should I do? I was benchmarking 2.4.1[68] some time ago and -Os helps gcc to produce faster code (both gcc 2.95.3 and 3.2.3). (It was Geode. But e.g. Motorolla's PowerQuicc has 16K L1 too - but I'm not sure does -Os help on ppc) On my test difference was around 5-7%. Task was very IO intensive with few of computational branches. Size of .text ~ 800K, .bss ~ 400K. > Please don't - I benchmarked it a while ago, and it's definitely slower. > If you have a puny 128K L2 cache, it might help, but it definitely needs > to be optional. Optional - would be Okay. P.S. That's dependency on GCC what should be optional. Let's not forget the source of the problem. -- Ihar 'Philips' Filipau / with best regards from Saarbruecken. -- "... and for $64000 question, could you get yourself vaguely familiar with the notion of on-topic posting?" -- Al Viro @ LKML