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: Tue, 16 Aug 2022 14:03:16 +0000 Message-ID: <325f95fd2b4bf15b4058@heytings.org> References: <1144021660321893@iva5-64778ce1ba26.qloud-c.yandex.net> <12348081660379417@sas2-a098efd00d24.qloud-c.yandex.net> <66bbbb95983414e79637@heytings.org> <83wnb9hadb.fsf@gnu.org> <395454dd-7238-c5d0-e924-2f65a186baa7@yandex.ru> <83r11hh4pm.fsf@gnu.org> <3a1232a17b09ce88af40@heytings.org> <4ebdfdc3-4aeb-7ebb-b5ba-43b5c9b0aaa1@yandex.ru> <3a1232a17b80387503f4@heytings.org> <881ac6c7-116c-49d0-8f19-4a3778260914@yandex.ru> <3a1232a17b37db7a2498@heytings.org> <3a1232a17bf656136616@heytings.org> <325f95fd2b09b959fddd@heytings.org> <325f95fd2b33afdbb5e6@heytings.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="37568"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 56682@debbugs.gnu.org, Eli Zaretskii , Dmitry Gutov To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Aug 16 16:05:57 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 1oNxCf-0009QB-4p for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 16 Aug 2022 16:05:57 +0200 Original-Received: from localhost ([::1]:52582 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oNxCd-0001HD-PT for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 16 Aug 2022 10:05:55 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44574) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oNxAp-0001Dz-JC for bug-gnu-emacs@gnu.org; Tue, 16 Aug 2022 10:04:06 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:58147) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1oNxAo-0000nK-6F for bug-gnu-emacs@gnu.org; Tue, 16 Aug 2022 10:04:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1oNxAn-00051G-VL for bug-gnu-emacs@gnu.org; Tue, 16 Aug 2022 10:04:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Gregory Heytings Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 16 Aug 2022 14:04:01 +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=B56682.166065859919244 (code B ref 56682); Tue, 16 Aug 2022 14:04:01 +0000 Original-Received: (at 56682) by debbugs.gnu.org; 16 Aug 2022 14:03:19 +0000 Original-Received: from localhost ([127.0.0.1]:47896 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oNxA7-00050K-G6 for submit@debbugs.gnu.org; Tue, 16 Aug 2022 10:03:19 -0400 Original-Received: from heytings.org ([95.142.160.155]:55954) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oNxA5-00050C-Ky for 56682@debbugs.gnu.org; Tue, 16 Aug 2022 10:03:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heytings.org; s=20220101; t=1660658597; bh=VIlazeB9hgzG/I1XRP4GBUMLLF/u9CAtGkwUmnTuotE=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:From; b=HuvAucOl5EiYrhsh2Sc7W57+UGI0QNbxnD3rx3UQFpy+8h667Zo/m2VfDkV/wUJ5u MP+IwuakdugEirV/q7fgMuRnxAlw+7pvE+TwQ9X7GA8Kmfu5U3UXn4/FdxmLbj0Z2d pzhl+4FW6U/qluiShaMB1mOPVJzCUDMfrHfnmJGCoEIk5MydiOeJmu8pW2fYoeXLxk 9IFVHCXAIO5LeGGd0H8AxH52zmACViQD15Nw8NyEaTNzejChYTc8QQiaSgWQDaDWjg 6R/td8JF8E+yESKnPfoE1euNYcadNVdlJN8BWfdU7UaTcAI4lNYF5mkkBLYCn9WYgF wEDy9l7b6X4+Q== In-Reply-To: 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:239948 Archived-At: >> Without assuming that computers have infinitely fast CPUs, that is? > > If the font-lock rules to use in the buffer depend on whether the first > line of the buffer starts with #! or not, then your narrowing will break > them even tho they could work perfectly fine in a 1TB buffer without > requiring an infinitely fast CPU (since they don't need to scan the > whole buffer: just the region of interest plus the first 2 chars). > Why on earth should a font-lock rule check, inside each redisplay cycle, whether the first line of the buffer starts with #! or not? Isn't that an information that can, and in fact should, be cached?