From owner-freebsd-current Sat Sep 25 13:24:35 1999 Delivered-To: freebsd-current@freebsd.org Received: from dorifer.heim3.tu-clausthal.de (dorifer.heim3.tu-clausthal.de [139.174.243.252]) by hub.freebsd.org (Postfix) with ESMTP id E6CAF15141 for ; Sat, 25 Sep 1999 13:24:30 -0700 (PDT) (envelope-from olli@dorifer.heim3.tu-clausthal.de) Received: (from olli@localhost) by dorifer.heim3.tu-clausthal.de (8.8.8/8.8.8) id WAA22407 for freebsd-current@FreeBSD.ORG; Sat, 25 Sep 1999 22:24:29 +0200 (CEST) (envelope-from olli) Date: Sat, 25 Sep 1999 22:24:29 +0200 (CEST) From: Oliver Fromme Message-Id: <199909252024.WAA22407@dorifer.heim3.tu-clausthal.de> To: freebsd-current@FreeBSD.ORG Subject: Re: gcc optimizer in -current system ... Organization: Administration Heim 3 Reply-To: freebsd-current@FreeBSD.ORG MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: TIN [version 1.2 RZTUC(3) PL2] Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Just some numbers that I got with a small testsuite. This is the setiathome client running on an AMD Athlon-500 (K7), FreeBSD 4.0-current (as of 1999-09-18). Of course, I've used the same work unit for all tests. I also changed the code to stop after a certain amount of data has processed, because I don't want to wait some hours for each test to complete. ;-) -O1 302.72 real 301.96 user 0.28 sys -O2 315.20 real 314.42 user 0.18 sys -O3 320.01 real 319.23 user 0.35 sys -Os 315.99 real 315.19 user 0.35 sys As you can see, -O1 is fastest, the higher optimization levels are slower. I'm currently running a testsuite with a larger number of optimizer flags combinations, but it'll take a while. On a side note, I downloaded AMD's document about optimizing code for the Athlon, and I found out that gcc does a pretty poor job. :-( Unfortunately, I'm not an expert in writing compilers, and I don't dare to touch the gcc source code. After all, the compiler is one of the most critical parts of the system. Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message