From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: The Emacs master is much slower than the emacs-27 branch. Date: Sat, 05 Dec 2020 17:14:08 +0200 Message-ID: <83y2icb7zz.fsf@gnu.org> References: <83wnxxcmjr.fsf@gnu.org> <83tut0d7e9.fsf@gnu.org> <83h7p0d37y.fsf@gnu.org> <83ft4kd2ym.fsf@gnu.org> <83eek4d2co.fsf@gnu.org> <87wnxwuzt0.fsf@tcd.ie> <83360kconl.fsf@gnu.org> <20201205145622.e4clewt4iq27q7g6@Ergus> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="27868"; mail-complaints-to="usenet@ciao.gmane.io" Cc: contovob@tcd.ie, ghe@sdf.org, stephen.berman@gmx.net, emacs-devel@gnu.org, acm@muc.de To: Ergus Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Dec 05 16:15:13 2020 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 1klZHF-00077S-4X for ged-emacs-devel@m.gmane-mx.org; Sat, 05 Dec 2020 16:15:13 +0100 Original-Received: from localhost ([::1]:44600 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1klZHE-0002wR-4t for ged-emacs-devel@m.gmane-mx.org; Sat, 05 Dec 2020 10:15:12 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:34324) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1klZGV-0002V9-8z for emacs-devel@gnu.org; Sat, 05 Dec 2020 10:14:27 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:46926) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1klZGS-0004dS-Fk; Sat, 05 Dec 2020 10:14:24 -0500 Original-Received: from [176.228.60.248] (port=4620 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1klZGR-0005dE-Rm; Sat, 05 Dec 2020 10:14:24 -0500 In-Reply-To: <20201205145622.e4clewt4iq27q7g6@Ergus> (message from Ergus on Sat, 5 Dec 2020 15:56:22 +0100) 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:260367 Archived-At: > Date: Sat, 5 Dec 2020 15:56:22 +0100 > From: Ergus > Cc: "Basil L. Contovounesios" , ghe@sdf.org, acm@muc.de, > stephen.berman@gmx.net, emacs-devel@gnu.org > > The best approach is maybe what Gregory did. Bisect the history to find > the source of the slowdown. Sure, if someone can afford that, it would be nice to know. Assuming a single commit causes it, that is (it could be several commits instead, each one slowing down Emacs by a few percents). When I said "not too bad", it didn't mean we should disregard it, just that it's much less than Alan originally reported, which would be alarming. > Actually in my work we have a log where we register the changes and the > commits hashes that impacted performance more than 5-7% either to > improve or degrade it. That requires to have a representative test suite which to use for such benchmarking. For Emacs this is not easy; for example, no one said that Alan's benchmark is representative of what Emacs does most of the time in "normal" usage. Personally, I don't think we should even try to come up with single benchmark. We should instead have several, and make sure we understand and/or fix slowdown in any one of them. Volunteers are welcome to work on a suite of such benchmarks, we could then put them under test/ somewhere.