From owner-freebsd-alpha Wed May 15 0:55:52 2002 Delivered-To: freebsd-alpha@freebsd.org Received: from gnah.bolet.org (gnah.bolet.org [80.65.226.87]) by hub.freebsd.org (Postfix) with ESMTP id 88E7B37B405 for ; Wed, 15 May 2002 00:55:48 -0700 (PDT) Received: (from pornin@localhost) by gnah.bolet.org (8.11.6/8.11.6) id g4F7tk250706 for alpha@FreeBSD.org; Wed, 15 May 2002 09:55:46 +0200 (CEST) (envelope-from pornin) Date: Wed, 15 May 2002 09:55:44 +0200 From: Thomas Pornin To: alpha@FreeBSD.org Subject: Re: Alpha CPU Performance vs i386 Message-ID: <20020515095544.A50576@gnah.bolet.org> References: <20020514201923.GK37326@Area51.DK> <20020514222344.A2915@freebie.xs4all.nl> <20020515161627.O18023@gsmx07.alcatel.com.au> <20020515093259.A50064@gnah.bolet.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <20020515093259.A50064@gnah.bolet.org>; from pornin@bolet.org on Wed, May 15, 2002 at 09:33:00AM +0200 Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Wed, May 15, 2002 at 09:33:00AM +0200, Thomas Pornin wrote: > I have used as my main working machine a Miata for three years (under > Linux first, then FreeBSD) and I came to the following conclusions: I forgot one point which seems to me to be of some importance: Alpha are slow at compiling C code. It is not specific to the Alpha architecture, it is just that gcc is slow. I have been told that the register allocator in gcc uses an algorithm which is exponential in the number of available registers. A PC has 6 or 7 generic-purpose registers, an Alpha has 31... The Compaq compiler is slow also, but I think it is general sloppiness that is often seen in big software from big companies. It produces really good code, though (I often observed a 30% improvement in speed over gcc on generic integer code). I have been looking for a decent, fast C compiler on the Alpha, and I found none. Lcc is completely buggy on the Alpha/OSF, and is anyway not up-to-date with regards to C99. TenDRA was not fast, and seemed to be quite peckish about its own interpretation of what is portable. Maybe I overlooked something ? --Thomas Pornin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message