From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Gregory Heytings Newsgroups: gmane.emacs.bugs Subject: bug#56682: Fix the long lines font locking related slowdowns Date: Fri, 05 Aug 2022 11:50:56 +0000 Message-ID: <92da07bd02f5963a2da4@heytings.org> References: <83pmhuft5a.fsf@gnu.org> <05388e8d8836c2e7ef3e@heytings.org> <136c4fe0fcb9ce5181cb@heytings.org> <3d639ea12689d767ba2a@heytings.org> <838ro44fc8.fsf@gnu.org> <3d639ea126d759bddfea@heytings.org> <83y1w42vp4.fsf@gnu.org> <3d639ea12618e6a503af@heytings.org> <83wnbo2uw3.fsf@gnu.org> <3d639ea126e3a4d880b8@heytings.org> <83k07o2izh.fsf@gnu.org> <3d639ea1265c40a07f40@heytings.org> <83h72s2e3o.fsf@gnu.org> <3d639ea126c6b0c6737b@heytings.org> <838ro42b1g.fsf@gnu.org> <3d639ea126db3913202e@heytings.org> <83wnbn264f.fsf@gnu.org> <3d639ea12684115449f8@heytings.org> <83tu6r1b03.fsf@gnu.org> <92da07bd02b96d54dbf4@heytings.org> <835yj62a18.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4520"; mail-complaints-to="usenet@ciao.gmane.io" Cc: gerd.moellmann@gmail.com, 56682@debbugs.gnu.org, monnier@iro.umontreal.ca, dgutov@yandex.ru To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri Aug 05 13:51:34 2022 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1oJvrZ-0000yK-S7 for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 05 Aug 2022 13:51:34 +0200 Original-Received: from localhost ([::1]:56870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oJvrY-0004wm-Sj for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 05 Aug 2022 07:51:32 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:43016) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJvr4-0004uO-97 for bug-gnu-emacs@gnu.org; Fri, 05 Aug 2022 07:51:11 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:38441) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1oJvr3-00080V-W7 for bug-gnu-emacs@gnu.org; Fri, 05 Aug 2022 07:51:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1oJvr3-0005Gh-SF for bug-gnu-emacs@gnu.org; Fri, 05 Aug 2022 07:51:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Gregory Heytings Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 05 Aug 2022 11:51:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 56682 X-GNU-PR-Package: emacs Original-Received: via spool by 56682-submit@debbugs.gnu.org id=B56682.165970026020244 (code B ref 56682); Fri, 05 Aug 2022 11:51:01 +0000 Original-Received: (at 56682) by debbugs.gnu.org; 5 Aug 2022 11:51:00 +0000 Original-Received: from localhost ([127.0.0.1]:56423 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oJvr2-0005GS-Er for submit@debbugs.gnu.org; Fri, 05 Aug 2022 07:51:00 -0400 Original-Received: from heytings.org ([95.142.160.155]:40252) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oJvr0-0005GJ-1D for 56682@debbugs.gnu.org; Fri, 05 Aug 2022 07:50:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heytings.org; s=20220101; t=1659700256; bh=8T403p3eJAEg4OI+wVLI//Ue4PHAA4blEgE495kNc5s=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:From; b=HfNMdaC0WKb8j98FzMzLdAbtC2pHaHm7LHWBE4bk6JDDxPjx/DNognzzzfRmvbixv gpKlnorZEaDlR+BhkgyqUpHsLmUcj7EHfEwGWteiYJv5yqSsDWhb1YxoQ94xILFmV1 wdIVI5wJzGrKCtBKFQfeYOTBYUANL0hrur8Mdv5YwqlfgNM2jSJo7zvv9D66ebmuwq K8890o7mNRo98AFsfnNuNC2pSh4soDp9bfC6GQqjdx6ujjW4aUfMqOaEm9I+Vo2XNH H6CEUQssBjed/CfyPL7xWIkJgjMiBGgjcoAdGxzAJ2X8BZNUz/L2HilHIjg8Iv2rmW 2XW6bDihc9gXg== In-Reply-To: <835yj62a18.fsf@gnu.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:238869 Archived-At: > > There's (at least) one more aspect of this, as long as Text mode is > being used: Text mode doesn't force bidi-paragraph-direction to be > left-to-right, whereas all descendants of prog-mode, including js-mode, > do. Leaving bidi-paragraph-direction at nil means Emacs needs to > determine the base paragraph direction each time it's about to redisplay > a window, and that might be expensive, especially in a large buffer > without any paragraph breaks (by default, an empty line), because that > is determined by the first strong directional character of the > paragraph. So for a more fair comparison with Text mode, you should set > bidi-paragraph-direction to the value left-to-right in text-mode > buffers. > Indeed, that seems to be the culprit here, I didn't know that text-mode was an exception here. If I set bidi-paragraph-direction to 'left-to-right after visiting the arabic-small.txt file, Emacs (mis) behaves like it does for the other Arabic files: it becomes slow, and C-n C-p do not work correctly anymore.