From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Emacs Lisp JIT Compiler Date: Sun, 12 Aug 2018 22:37:25 -0700 Organization: UCLA Computer Science Department Message-ID: References: <87va8ej4o1.fsf@tromey.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1534138537 23989 195.159.176.226 (13 Aug 2018 05:35:37 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 13 Aug 2018 05:35:37 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 To: Tom Tromey , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Aug 13 07:35:33 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fp5Vt-00068r-7z for ged-emacs-devel@m.gmane.org; Mon, 13 Aug 2018 07:35:33 +0200 Original-Received: from localhost ([::1]:37652 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fp5Xz-0000Ax-OT for ged-emacs-devel@m.gmane.org; Mon, 13 Aug 2018 01:37:43 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:50063) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fp5Xt-0000Ar-0b for emacs-devel@gnu.org; Mon, 13 Aug 2018 01:37:37 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fp5Xp-0004BP-S4 for emacs-devel@gnu.org; Mon, 13 Aug 2018 01:37:37 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:49122) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fp5Xp-0004B5-Kr for emacs-devel@gnu.org; Mon, 13 Aug 2018 01:37:33 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 416F4160661; Sun, 12 Aug 2018 22:37:32 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id dm2Irc5y0SYV; Sun, 12 Aug 2018 22:37:31 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 8CF5D16072A; Sun, 12 Aug 2018 22:37:31 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id TYx_zUC7dPKm; Sun, 12 Aug 2018 22:37:31 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.30.119]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 4B5C8160661; Sun, 12 Aug 2018 22:37:31 -0700 (PDT) In-Reply-To: <87va8ej4o1.fsf@tromey.com> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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" Xref: news.gmane.org gmane.emacs.devel:228466 Archived-At: This sounds very interesting. I assume you'd publish it first on a branch so that we could look at it? Some questions: > I have only tested this on x86-64. Whether or not the JIT works on a > given platform is primarily up to libjit. (I suspect the JIT won't work > on x86 with --with-wide-int; but that is something I could fix.) When you say "doesn't work", does that mean Emacs can reliably tell the JIT won't work and fall back on the current bytecode implementation, or something else? > libjit never frees functions. So, if a function is JIT-compiled > and then redefined, the old JIT code will linger. It's possible to fix > this with a custom allocator and a libjit patch (that I sent but that > hasn't been checked in yet). libjit has only one committer, Aleksey, and no commits since March. Is there a bottleneck there?