Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964808AbWCGXha (ORCPT ); Tue, 7 Mar 2006 18:37:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964810AbWCGXh3 (ORCPT ); Tue, 7 Mar 2006 18:37:29 -0500 Received: from mail.gmx.net ([213.165.64.20]:29608 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S964808AbWCGXh3 (ORCPT ); Tue, 7 Mar 2006 18:37:29 -0500 X-Authenticated: #428038 Date: Wed, 8 Mar 2006 00:37:24 +0100 From: Matthias Andree To: Lee Revell Cc: Silviu Marin-Caea , opensuse-factory@opensuse.org, linux-kernel@vger.kernel.org Subject: Re: [opensuse-factory] Re[2]: 2.6.16 serious consequences / GPL_EXPORT_SYMBOL / USB drivers of major vendor excluded Message-ID: <20060307233724.GB13357@merlin.emma.line.org> Mail-Followup-To: Lee Revell , Silviu Marin-Caea , opensuse-factory@opensuse.org, linux-kernel@vger.kernel.org References: <200603070942.31774.silviu_marin-caea@fieldinsights.ro> <1141769422.767.99.camel@mindpipe> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1141769422.767.99.camel@mindpipe> X-PGP-Key: http://home.pages.de/~mandree/keys/GPGKEY.asc User-Agent: Mutt/1.5.11 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 30 On Tue, 07 Mar 2006, Lee Revell wrote: > If they are doing serious realtime DSP then they should get better > results in userspace anyway, because they get to use the floating point > unit which isn't allowed in the kernel. It's not as though every algorithm needed float just because it said DSP (some of those are actually fixed-point or something like that) at a time. There are lots of algorithms to avoid exactly that, because it costs performance big time. Whenever you can have integer and/or reduce/approximate multiplication by shift+add, people will use it if performance is of paramount importance. And such often is the difference between having a real-time DRM software radio or not, to name just one example I've seen in my vicinity. In a color-space conversion tool (CCITT YUV to RGB) on P-II or P-III (don't recall) emulating fixed point by using integers and then shifting appropriately gave a speedup of well more than three. There must surely be better and reasons than the FPU - licenses had already been mentioned. -- Matthias Andree - 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/