From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Benchmarking temporary Lisp objects [Was: Re: [RFC] temporary Lisp_Strings] Date: Fri, 05 Sep 2014 00:24:28 -0400 Message-ID: References: <5405BE5D.1090003@yandex.ru> <5405DE8B.4050201@yandex.ru> <5406EC21.4060200@yandex.ru> <5407281C.3090302@cs.ucla.edu> <54073621.2040403@yandex.ru> <540744F5.2010804@cs.ucla.edu> <5407F1B7.6090704@yandex.ru> <5407F4E6.2040809@cs.ucla.edu> <5407FDF4.7020504@yandex.ru> <54086B1A.8070506@yandex.ru> <54087B5E.10402@yandex.ru> <54088D63.8010406@cs.ucla.edu> <54093561.2010507@yandex.ru> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1409891118 21776 80.91.229.3 (5 Sep 2014 04:25:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 5 Sep 2014 04:25:18 +0000 (UTC) Cc: Paul Eggert , Emacs development discussions To: Dmitry Antipov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Sep 05 06:25:10 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XPl5C-0005IG-Pr for ged-emacs-devel@m.gmane.org; Fri, 05 Sep 2014 06:25:10 +0200 Original-Received: from localhost ([::1]:55391 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XPl5C-0001I0-AD for ged-emacs-devel@m.gmane.org; Fri, 05 Sep 2014 00:25:10 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:37218) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XPl4s-0001Ht-VL for emacs-devel@gnu.org; Fri, 05 Sep 2014 00:24:58 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XPl4k-00043g-0Z for emacs-devel@gnu.org; Fri, 05 Sep 2014 00:24:50 -0400 Original-Received: from chene.dit.umontreal.ca ([132.204.246.20]:36008) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XPl4j-00041Y-SE for emacs-devel@gnu.org; Fri, 05 Sep 2014 00:24:41 -0400 Original-Received: from fmsmemgm.homelinux.net (lechon.iro.umontreal.ca [132.204.27.242]) by chene.dit.umontreal.ca (8.14.1/8.14.1) with ESMTP id s854OSxg023702; Fri, 5 Sep 2014 00:24:29 -0400 Original-Received: by fmsmemgm.homelinux.net (Postfix, from userid 20848) id 0D8D5AE0D6; Fri, 5 Sep 2014 00:24:28 -0400 (EDT) In-Reply-To: <54093561.2010507@yandex.ru> (Dmitry Antipov's message of "Fri, 05 Sep 2014 08:00:33 +0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) X-NAI-Spam-Flag: NO X-NAI-Spam-Threshold: 5 X-NAI-Spam-Score: 0 X-NAI-Spam-Rules: 1 Rules triggered RV5054=0 X-NAI-Spam-Version: 2.3.0.9378 : core <5054> : inlines <1245> : streams <1281739> : uri <1810459> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 132.204.246.20 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:174027 Archived-At: > alloca/fallback to regular GC for vectors and strings. Stefan? I'm definitely in favor of a simple solution. So far I haven't seen compelling evidence that such alloca tricks are even worthwhile at all. Your benchmark for `cons' showed that there's some potential benefit, but then we have to figure out which Fcons calls can be replaced by alloca ones, and then assess whether the result is worth the effort (and the risk, since such alloca-allocated thingies need to be handled with care, making sure they can't escape to Elisp, and also using the stack more intensively increases the risk of crashing into the stack depth limit). Stefan