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: Thu, 04 Aug 2022 18:16:02 +0000 Message-ID: <3d639ea126db3913202e@heytings.org> References: <837d43j198.fsf@gnu.org> <83y1wjhkkh.fsf@gnu.org> <83wnc3hkdg.fsf@gnu.org> <49df74e5-e16a-a532-98d1-66c6ff1eb6c6@yandex.ru> <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> 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="31445"; 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 Thu Aug 04 20:17:50 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 1oJfPo-0007vb-Vt for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 04 Aug 2022 20:17:49 +0200 Original-Received: from localhost ([::1]:51006 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oJfPn-0005jO-Gw for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 04 Aug 2022 14:17:47 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:60726) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJfP4-0005in-AZ for bug-gnu-emacs@gnu.org; Thu, 04 Aug 2022 14:17:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:36872) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1oJfP4-00017l-1a for bug-gnu-emacs@gnu.org; Thu, 04 Aug 2022 14:17:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1oJfP3-00069W-RQ for bug-gnu-emacs@gnu.org; Thu, 04 Aug 2022 14:17:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Gregory Heytings Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 04 Aug 2022 18:17:01 +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=B56682.165963696823584 (code B ref 56682); Thu, 04 Aug 2022 18:17:01 +0000 Original-Received: (at 56682) by debbugs.gnu.org; 4 Aug 2022 18:16:08 +0000 Original-Received: from localhost ([127.0.0.1]:54854 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oJfOC-00068K-E2 for submit@debbugs.gnu.org; Thu, 04 Aug 2022 14:16:08 -0400 Original-Received: from heytings.org ([95.142.160.155]:39168) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oJfO8-000689-I2 for 56682@debbugs.gnu.org; Thu, 04 Aug 2022 14:16:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heytings.org; s=20220101; t=1659636963; bh=qlnqABqk8K+nmCNZcPsRWA7T/j7kXJ8lbKI98mpb/UM=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:From; b=bZu7jpE2OkojsIAzkpyy5c3IJxzUSxXfkJyNN4mW2gZagOqqgNN9PNfYHVPQqYZa3 cVjN14CCSnG/TtcQc0PwDj/R67bBH9Jot3oSq+aO8tH1pKUXO/yfECNFeP+Q9Bulqd W31WMwRPov7fp8r4d3GAa4h4C8gdeAv1JrwGc4Ys6SJ5GE57d8na/jxnxT+eXOHmlB wKchYN9CgrDefzUNYqLwnLxLlIIcFPtdXPEFaNv7zaPFOFxBfPIB8y9AUUwjEflc3Q J+6IPtCRbPN2tX+z41G52szyUo3iUy1I1rxcteq5oeNchp51Oqp4+FLAStIadh3f1h TeEOPHx4g7QsA== In-Reply-To: <838ro42b1g.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:238784 Archived-At: >> It's not really "almost instantaneous", moving point can take >> (depending on factors I do not understand at the moment) something >> between 0.2 seconds and 2 seconds. > > I saw slower response when point was at a parentesis or a brace -- due > to show-paren-mode. Try disabling it and see if that affects > performance. > I forgot to mention that this is with show-paren-mode disabled. > > Another problem could be the BPA algorithm in bidi.c, but in my testing > setting bidi-inhibit-bpa non-nil didn't affect performance in any > tangible way, with this file. > Indeed. > > More accurately, Arabic text needs to call the shaping engine (HarfBuzz) > for all the characters, whereas Hebrew does that only rarely (and not at > all in locales.json). You can see from the composition rules in, > respectively, lisp/language/misc-lang.el and lisp/language/hebrew.el > that for Arabic, the entire range of Arabic characters is populated with > composition rules in composition-function-table, whereas for Hebrew, > only some relatively rare characters have non-nil rules. > Okay, thanks! >> Hmmm... I still think it would be possible to do better. With the >> above recipe (M-g g 70000 RET C-n), composition_compute_stop_pos is >> called 627663 times and uses about 2 seconds of CPU time. What >> surprises me (and makes me believe it's perhaps possible to do better) >> is that it is called repeatedly with the same arguments. For example, >> when doing C-n it is called 26 times with charpos = 69980. > > I'll see where these come from and whether some of them could be > avoided. > > Are you capable of running under perf and producing the profile of these > commands? Because I wonder whether we correctly identify the main > bottlenecks in these scenarios. > I can't speak in general, but in this particular scenario, the bottleneck is clearly composition_compute_stop_pos. You didn't tell me whether it's okay to merge the branch with the latest changes?