From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Crashes in "C-h h" Date: Thu, 4 Jul 2019 00:15:12 -0700 Organization: UCLA Computer Science Department Message-ID: References: <83y31hes6r.fsf@gnu.org> <83r279epwe.fsf@gnu.org> <09f72051-d740-9115-c6fd-c4344c749568@cs.ucla.edu> <83muhvd9nm.fsf@gnu.org> <9b78b85d-a3c8-761f-e500-d51d4a985fa8@cs.ucla.edu> <83k1cybk8c.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="202759"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 Cc: pipcet@gmail.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Jul 04 09:16:29 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hivym-000qaH-R3 for ged-emacs-devel@m.gmane.org; Thu, 04 Jul 2019 09:16:28 +0200 Original-Received: from localhost ([::1]:43244 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hivyl-0004dn-39 for ged-emacs-devel@m.gmane.org; Thu, 04 Jul 2019 03:16:27 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:45947) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hivxd-0004de-Hg for emacs-devel@gnu.org; Thu, 04 Jul 2019 03:15:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hivxc-0005AV-KR for emacs-devel@gnu.org; Thu, 04 Jul 2019 03:15:17 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:43524) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hivxb-00058r-5i; Thu, 04 Jul 2019 03:15:15 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 6BBDE161DC4; Thu, 4 Jul 2019 00:15:13 -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 2yEQlTyvsryP; Thu, 4 Jul 2019 00:15:12 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id B0C7E1626A6; Thu, 4 Jul 2019 00:15:12 -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 RhLI3W6C51GG; Thu, 4 Jul 2019 00:15:12 -0700 (PDT) Original-Received: from [192.168.1.9] (cpe-23-242-74-103.socal.res.rr.com [23.242.74.103]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 80DFF161DC4; Thu, 4 Jul 2019 00:15:12 -0700 (PDT) In-Reply-To: <83k1cybk8c.fsf@gnu.org> 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: 2.1.23 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:238348 Archived-At: Eli Zaretskii wrote: > Is this with USE_LSB or without? I think we need to time both > variants. That benchmark was with USE_LSB. I see no reason to think the !USE_LSB case would cause FIXNUMP+XFIXNUM to beat EQ+make_fixnum, but just to double-check here are the timings for that benchmark compiled with the additional GCC flags -m32 -DWIDE_EMACS_INT (the only significant !USE_LSB platform these days) and with 'long' replaced by 'long long' to get the loop to work on a 32-bit platform: 1030-lnxsrv09 $ time ./a.out 0 0 real 0m51.933s user 0m51.927s sys 0m0.001s 1031-lnxsrv09 $ time ./a.out 0 0 0 real 2m16.960s user 2m16.960s sys 0m0.000s 1032-lnxsrv09 $ time ./a.out 0 0 0 0 real 0m59.678s user 0m59.677s sys 0m0.001s This indicates that on this !USE_LSB platform, the EQ+make_fixnum code is about ten times faster than the FIXNUMP+XFIXNUM code on this benchmark. I'm not surprised by the performance disparity, as branch-prediction failures can be pretty expensive.