From owner-freebsd-current Wed May 26 1:39:10 1999 Delivered-To: freebsd-current@freebsd.org Received: from ipt2.iptelecom.net.ua (ipt2.iptelecom.net.ua [212.42.68.2]) by hub.freebsd.org (Postfix) with ESMTP id 8B54C15484 for ; Wed, 26 May 1999 01:38:58 -0700 (PDT) (envelope-from sobomax@altavista.net) Received: from vega. (dialup1-43.iptelecom.net.ua [212.42.68.170]) by ipt2.iptelecom.net.ua (8.9.3/8.9.3) with ESMTP id LAA12827; Wed, 26 May 1999 11:39:45 +0300 (EEST) Received: from altavista.net (big_brother [192.168.1.1]) by vega. (8.9.3/8.9.3) with ESMTP id LAA52393; Wed, 26 May 1999 11:38:53 +0300 (EEST) (envelope-from sobomax@altavista.net) Message-ID: <374BA9CD.AC107917@altavista.net> Date: Wed, 26 May 1999 10:59:09 +0300 From: Maxim Sobolev Reply-To: sobomax@altavista.net Organization: Vega International Capital X-Mailer: Mozilla 4.6 [en] (WinNT; I) X-Accept-Language: ru,uk,en MIME-Version: 1.0 To: Garrett Wollman Cc: current@FreeBSD.ORG Subject: Re: More compiler option comparisons References: <199905251635.MAA11353@khavrinen.lcs.mit.edu> Content-Type: text/plain; charset=x-user-defined Content-Transfer-Encoding: 8bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Garrett Wollman wrote: > Just for completeness, I did one final run of HINT with just `-O' > specified (our usual default).  `-O' results in significantly better > integer performance than `-O4'.  (Floating-point performance is just > the opposite.) > > This suggests that compiling the world with `-O' levels higher than > one is probably a bad idea.  (The generated assembly is identical from > `-O2' to `-O4'.)  The `-O2' code appears to be less efficient at > register allocation; about twice as much stack temporary space is > required. > > For the graph, see . As my own test shown hint reporded benchmarks depend highly on options used to compile libm, so to get more accurate results your must consider to make libm with the same options used to compile hint (probably better to make several static versions of hint executable linked with the corresponding libm). Sincerely, Maxim To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message