From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: 26.2; Strange slowness in some Info nodes Date: Sat, 03 Aug 2019 09:48:10 +0300 Message-ID: <831ry2g2xh.fsf@gnu.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="74612"; mail-complaints-to="usenet@blaine.gmane.org" To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Aug 03 08:48:24 2019 Return-path: Envelope-to: geh-help-gnu-emacs@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 1htnq2-000JHn-UO for geh-help-gnu-emacs@m.gmane.org; Sat, 03 Aug 2019 08:48:23 +0200 Original-Received: from localhost ([::1]:38722 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1htnq1-0008Pr-Jb for geh-help-gnu-emacs@m.gmane.org; Sat, 03 Aug 2019 02:48:21 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54781) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1htnpu-0008PZ-Qz for help-gnu-emacs@gnu.org; Sat, 03 Aug 2019 02:48:15 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:53408) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1htnpu-0006Ax-O4 for help-gnu-emacs@gnu.org; Sat, 03 Aug 2019 02:48:14 -0400 Original-Received: from [176.228.60.248] (port=3090 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1htnpu-0008Ae-2E for help-gnu-emacs@gnu.org; Sat, 03 Aug 2019 02:48:14 -0400 In-reply-to: (message from ndame on Fri, 2 Aug 2019 20:23:06 +0000 (GMT)) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:121300 Archived-At: > Date: Fri, 2 Aug 2019 20:23:06 +0000 (GMT) > From: ndame > > Though I don't really get why repeated scrolling down is > slow. I'd think the first one is slow when emacs finds the font > for the character and then subsequent scroll downs should be > quick, because then the font for the character is known.  It is known, but that knowledge can be forgotten. > It would be strange if the cached information were purged from > memory right after it was found and emacs had to find the font > again for the next scroll down. It is purged during GC. At the GC level, there's no information available that could tell Emacs not to purge a font (the "right after" part is perhaps evident to a human, but not to a program). The basic problem with this situation is that some very large fonts cause very frequent GC, which evicts those large fonts, which then cause a lot of consing when they are again loaded, which again causes GC soon, etc.