From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758249Ab1IHKpK (ORCPT ); Thu, 8 Sep 2011 06:45:10 -0400 Received: from lo.gmane.org ([80.91.229.12]:38677 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758153Ab1IHKpI (ORCPT ); Thu, 8 Sep 2011 06:45:08 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Kristoff Bonne Subject: [Question] FastFPE math emulation Date: Thu, 08 Sep 2011 12:42:07 +0200 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: 91.181.69.100 User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.21) Gecko/20110831 Thunderbird/3.1.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I am playing around with a "friendlyarm mini2440" development board. It's a system based on a 400 Mhz samsung s3c2440 CPU, which is itself based on a ARM920T core. This system does not have a FPU. (nor integer DSP instruction-set). I want to experiment to use this board for audio-related application, e.g. the codec2 vocoder. The implementation of that codec is now based on floating-point math. First tests indicate that, using default settings, the board is not fast enough to do realtime encoding or decoding of codec2 . (encoding a 34 second audio-sample takes 42 seconds). Yesterday, I noticed the kernel has an option "FastFPE math emulation" but when I install a kernel with that option enabled, I see no difference at all. - does FastFPE work on this kind of CPU. - Is there something that needs to be done to activate it? (setting, option during compiling, ...?) Info: # uname -a Linux FriendlyARM 2.6.32.2-FriendlyARM #9 Wed Sep 7 21:38:49 CEST 2011 armv4tl unknown $ grep -i fpe .config CONFIG_FPE_NWFPE=y # CONFIG_FPE_NWFPE_XP is not set CONFIG_FPE_FASTFPE=y # cat /proc/cpuinfo Processor : ARM920T rev 0 (v4l) BogoMIPS : 201.93 Features : swp half CPU implementer : 0x41 CPU architecture: 4T CPU variant : 0x1 CPU part : 0x920 CPU revision : 0 Hardware : FriendlyARM Mini2440 development board Revision : 0000 Serial : 0000000000000000 http://friendlyarm.net/products/mini2440?lang=en http://codec2.org/ Cheerio! Kr. Bonne.