From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: bug-reference-prog-mode slows down CC Mode's scrolling by ~7% Date: Wed, 1 Sep 2021 17:55:46 +0000 Message-ID: References: <83r1e8p4w8.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="21819"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Sep 01 19:57:00 2021 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 1mLUTr-0005R0-RV for ged-emacs-devel@m.gmane-mx.org; Wed, 01 Sep 2021 19:56:59 +0200 Original-Received: from localhost ([::1]:59200 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mLUTp-000864-N5 for ged-emacs-devel@m.gmane-mx.org; Wed, 01 Sep 2021 13:56:57 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:57016) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mLUSl-0006m8-Fk for emacs-devel@gnu.org; Wed, 01 Sep 2021 13:55:51 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:24112 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1mLUSj-0008KZ-7B for emacs-devel@gnu.org; Wed, 01 Sep 2021 13:55:51 -0400 Original-Received: (qmail 10548 invoked by uid 3782); 1 Sep 2021 17:55:46 -0000 Original-Received: from acm.muc.de (p4fe15865.dip0.t-ipconnect.de [79.225.88.101]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 01 Sep 2021 19:55:46 +0200 Original-Received: (qmail 6856 invoked by uid 1000); 1 Sep 2021 17:55:46 -0000 Content-Disposition: inline In-Reply-To: <83r1e8p4w8.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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:273677 Archived-At: Hello, Eli. On Wed, Sep 01, 2021 at 20:44:23 +0300, Eli Zaretskii wrote: > > Date: Wed, 1 Sep 2021 17:33:06 +0000 > > From: Alan Mackenzie > > When applied to C Mode, bug-reference-prog-mode slows down a scroll from > > point-min to point-max by around 7%. > > Just how useful is bug-reference-prog-mode? Is it really worth this 7% > > slowdown? > It is marginally useful, but 7% slowdown is too heavy a price, IMO. > This should be fixed. I agree. > (I thought that the code in jit-lock.el already handled this case by > computing a kind-of "maximum" out of all the return values of > jit-lock-functions, and treating a nil return value as expected, but > maybe my reading of the code was incorrect?) I think it rather uses the "minimum", i.e. the region common to all the return values from the jit-lock-functions. If one of these values is nil (as is the case here), that boils down to exactly the 500-byte chunk. The comments in jit-lock.el say that this happens, and half-propose a mechanism for fixing it. It doesn't look straightforward to fix. -- Alan Mackenzie (Nuremberg, Germany).