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 17:08:44 +0200 Message-ID: <83zh2sb88z.fsf@gnu.org> References: <877dpyzg9d.fsf@rub.de> <87czzpsyqn.fsf@gmx.net> <83o8j9eqwx.fsf@gnu.org> <874kl1spe9.fsf@gmx.net> <83blf9em55.fsf@gnu.org> <87zh2tr82r.fsf@gmx.net> <87v9dhr7i5.fsf@gmx.net> <838sadefiw.fsf@gnu.org> <83360le421.fsf@gnu.org> <83y2idcn8q.fsf@gnu.org> <83wnxxcmjr.fsf@gnu.org> <83tut0d7e9.fsf@gnu.org> <8c5fe90c-72ca-a2c3-29d2-1849458bb85a@gmx.at> <87wnxwwbqz.fsf@telefonica.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="5708"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: =?iso-8859-1?Q?=D3scar?= Fuentes Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Dec 05 16:09:51 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 1klZC3-0001OW-JZ for ged-emacs-devel@m.gmane-mx.org; Sat, 05 Dec 2020 16:09:51 +0100 Original-Received: from localhost ([::1]:39448 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1klZC2-0000ZC-KK for ged-emacs-devel@m.gmane-mx.org; Sat, 05 Dec 2020 10:09:50 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:60864) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1klZBF-00088x-1y for emacs-devel@gnu.org; Sat, 05 Dec 2020 10:09:01 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:46852) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1klZBE-0002fW-0X; Sat, 05 Dec 2020 10:09:00 -0500 Original-Received: from [176.228.60.248] (port=4284 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1klZBD-00054R-8L; Sat, 05 Dec 2020 10:08:59 -0500 In-Reply-To: <87wnxwwbqz.fsf@telefonica.net> (message from =?iso-8859-1?Q?=D3scar?= Fuentes on Sat, 05 Dec 2020 15:47:32 +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:260365 Archived-At: > From: Óscar Fuentes > Date: Sat, 05 Dec 2020 15:47:32 +0100 > > -Og is the recommended setting for the edit/build/debug cycle [1], > because it *improves* debug info accuracy over -O0 *and* also runs > faster, which is a significant bonus. So IMHO it is a good thing to not > regress -Og too much. -O0, on the other hand, shouldn't be a concern. Actually, my experience is that during development one should use -O0, since even -Og sometimes messes up the code and backtrace so much that GDB is unable to show variables or produce a reasonably accurate backtrace. But of course -O2 is of the main concern when slowdown is reported. FWIW, I think the "original sin" here is the preference of inline functions to C macros. We would never have such problems if we continued to use old and time-proven macros instead of converting a large portion of them to inline functions, which caused us portability problems and this issue, among others.