From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Is Emacs buffer scroll/redisplay slow? Date: Sun, 19 Jan 2020 11:51:46 +0000 Message-ID: <20200119115146.GA9172@ACM> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="22072"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Emacs developers To: Fabrice Popineau Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Jan 19 12:53:02 2020 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 1it98X-0005fJ-PE for ged-emacs-devel@m.gmane-mx.org; Sun, 19 Jan 2020 12:53:01 +0100 Original-Received: from localhost ([::1]:49536 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1it98W-0000WA-Qk for ged-emacs-devel@m.gmane-mx.org; Sun, 19 Jan 2020 06:53:00 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55437) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1it97Q-0007y0-Uh for emacs-devel@gnu.org; Sun, 19 Jan 2020 06:51:53 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1it97P-0002z0-R1 for emacs-devel@gnu.org; Sun, 19 Jan 2020 06:51:52 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:10164 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1it97P-0002xk-Gq for emacs-devel@gnu.org; Sun, 19 Jan 2020 06:51:51 -0500 Original-Received: (qmail 99888 invoked by uid 3782); 19 Jan 2020 11:51:48 -0000 Original-Received: from acm.muc.de (p4FE15C7F.dip0.t-ipconnect.de [79.225.92.127]) by colin.muc.de (tmda-ofmipd) with ESMTP; Sun, 19 Jan 2020 12:51:46 +0100 Original-Received: (qmail 9669 invoked by uid 1000); 19 Jan 2020 11:51:46 -0000 Content-Disposition: inline In-Reply-To: X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 193.149.48.1 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:244367 Archived-At: Hello, Fabrice. On Sun, Jan 19, 2020 at 10:34:07 +0100, Fabrice Popineau wrote: > Hi, > Out of curiosity, I timed 'emacs -Q' .... Which version of Emacs? > .... scrolling through an elisp buffer: I started the timer by hand and > scrolled down for 1000 lines .... How, exactly, did you do the scrolling? How did you stop the scrolling at 1000 lines? Do you get this slowness on any elisp buffer, or is it a particular one? > .... and it took 45s on Windows/WSL and 35s on Windows/native. That is slow indeed. > This is on a pretty decent laptop (core i7, 32Gb ram, 4k display) I > don't care about the difference here, but overall, I find it pretty > slow. Is there something that could be done to enhance it? What is the > main bottleneck here? Have you tried profiling this scrolling, yet? If not, I suggest you do, with M-x profiler-start , running the scrolling, then M-x profiler-report. In the report buffer, hit to get successively deeper results. This may well give you an idea where the slowness is happening. > Best regards, > Fabrice -- Alan Mackenzie (Nuremberg, Germany).