From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Aligned blocks management: obsolete? Date: Mon, 12 Dec 2011 10:27:24 -0800 Organization: UCLA Computer Science Department Message-ID: <4EE6478C.1020701@cs.ucla.edu> References: <4EE5B744.1090103@yandex.ru> <4EE60A93.9060401@yandex.ru> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1323714456 3583 80.91.229.12 (12 Dec 2011 18:27:36 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 12 Dec 2011 18:27:36 +0000 (UTC) Cc: emacs-devel@gnu.org To: Dmitry Antipov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Dec 12 19:27:32 2011 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RaAb6-0002d8-8h for ged-emacs-devel@m.gmane.org; Mon, 12 Dec 2011 19:27:32 +0100 Original-Received: from localhost ([::1]:59858 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RaAb5-0005WJ-OZ for ged-emacs-devel@m.gmane.org; Mon, 12 Dec 2011 13:27:31 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:45627) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RaAb3-0005UZ-Bt for emacs-devel@gnu.org; Mon, 12 Dec 2011 13:27:30 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RaAb2-0005Qh-7E for emacs-devel@gnu.org; Mon, 12 Dec 2011 13:27:29 -0500 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:60031) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RaAb2-0005QD-22 for emacs-devel@gnu.org; Mon, 12 Dec 2011 13:27:28 -0500 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id 9F606A60001; Mon, 12 Dec 2011 10:27:25 -0800 (PST) X-Virus-Scanned: amavisd-new at smtp.cs.ucla.edu Original-Received: from smtp.cs.ucla.edu ([127.0.0.1]) by localhost (smtp.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8wHVZPytYPg7; Mon, 12 Dec 2011 10:27:25 -0800 (PST) Original-Received: from penguin.cs.ucla.edu (Penguin.CS.UCLA.EDU [131.179.64.200]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id 34A8A39E8008; Mon, 12 Dec 2011 10:27:25 -0800 (PST) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 In-Reply-To: <4EE60A93.9060401@yandex.ru> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 131.179.128.62 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:146676 Archived-At: On 12/12/11 06:07, Dmitry Antipov wrote: > I suppose that any non-ancient glibc malloc > doesn't require such a glitch in lisp_align_malloc any more This sounds correct to me as well, though I can't cite chapter and verse offhand. Certainly the posix_memalign implementation has mutated significantly since glibc 2.3.2 came out in 2003, and any performance measurements based on 2.3.2 are suspect now. More generally, if some cruft was put into alloc.c long ago for performance reasons, and if we can no longer demonstrate that the cruft improves performance significantly on currently-used platforms, then surely it's OK to remove it after the feature freeze is over. Cruft like that has a real maintenance cost, and there's no point keeping it if it doesn't actually have a performance benefit.