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: Bignum performance (was: Shrinking the C core) Date: Fri, 11 Aug 2023 14:38:12 +0200 Message-ID: <875y5lkb4b.fsf@dataswamp.org> References: <20230809094655.793FC18A4654@snark.thyrsus.com> <87il9owg0f.fsf@yahoo.com> <83fs4rjq9j.fsf@gnu.org> <87jzu2tvfc.fsf@dataswamp.org> <87y1ih3mc1.fsf@localhost> <87h6p5kcek.fsf@dataswamp.org> <87msyxoj2t.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="27376"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:ZqwmnIlPbEhw1stxTaQmn7hGVwE= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Aug 11 15:04:49 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 1qURov-0006aI-41 for ged-emacs-devel@m.gmane-mx.org; Fri, 11 Aug 2023 15:04:49 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qURi3-0002Q4-DA; Fri, 11 Aug 2023 08:57:43 -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 1qURPN-0000Ck-CO for emacs-devel@gnu.org; Fri, 11 Aug 2023 08:38:25 -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 1qURPL-0001nX-LD for emacs-devel@gnu.org; Fri, 11 Aug 2023 08:38:25 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qURPJ-0003C3-HO for emacs-devel@gnu.org; Fri, 11 Aug 2023 14:38:21 +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: Fri, 11 Aug 2023 08:57:38 -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:308578 Archived-At: Ihor Radchenko wrote: > And the fact that we allocate many objects is related to > immutability of bignums. Every time we do (setq bignum (* > bignum fixint)), we abandon the old object holding BIGNUM > value and allocate a new bignum object with a new value. > Clearly, this allocation is not free and takes a lot of CPU > time. While the computation itself is fast. So this happens in Emacs C code, OK. > Maybe we could somehow re-use the already allocated bignum > objects, similar to what is done for cons cells (see > src/alloc.c:Fcons). Sounds reasonable :) -- underground experts united https://dataswamp.org/~incal