From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.devel Subject: Re: [PATCH] Re: Bignum performance (was: Shrinking the C core) Date: Wed, 16 Aug 2023 00:21:07 +0200 Message-ID: <87r0o4eylo.fsf@dataswamp.org> References: <87bkfartof.fsf@localhost> <175cf474-29c8-a482-072e-0de784ac59e8@gmail.com> <87o7jaqc31.fsf@localhost> <2d419e12-9239-de3e-47d0-38815a00025f@gmail.com> <87cyzqq7sx.fsf@localhost> <875y5gh075.fsf@dataswamp.org> <87zg2spcxo.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="33950"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:94Omw7Q2bhqqn4JOaov8pRpaIMQ= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Aug 16 04:21:57 2023 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qW6AX-0008aA-DO for ged-emacs-devel@m.gmane-mx.org; Wed, 16 Aug 2023 04:21:57 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qW69X-0007Hq-19; Tue, 15 Aug 2023 22:20:55 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qW2Pe-00076N-TC for emacs-devel@gnu.org; Tue, 15 Aug 2023 18:21:18 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qW2Pc-00012U-Hs for emacs-devel@gnu.org; Tue, 15 Aug 2023 18:21:18 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qW2Pa-0000tT-HV for emacs-devel@gnu.org; Wed, 16 Aug 2023 00:21:14 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: emacs-devel@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Tue, 15 Aug 2023 22:20:52 -0400 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:308784 Archived-At: Ihor Radchenko wrote: >> A pretty good optimization! :O >> >> But what kind of optimization is it? > > The commented "optimization" is: "Hey, SBCL, do not use > bignums. If ints overflow, so be it". ? But then how can the algorithm execute correctly? >> Still, isn't the rule of the "beat the benchmark" game to >> beat it as fast as possible? > > Yes, but when CBCL is orders of magnitude faster, it > indicates something conceptually wrong in the algo. 3x is > a matter of variation in the internal details (like extra > type checking in Elisp that Po Lu outlined). If you are saying the algorithm doesn't output correct data for the conventional conception of the Fibonacci algorithm, then that optimization and whatever time it makes isn't valid, I'll remove it this instant. Hm, maybe we need something like unit testing to confirm that the algorithms perform not just fast, but also as intended to solve whatever problem they were designed to ... -- underground experts united https://dataswamp.org/~incal