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: Time to merge scratch/correct-warning-pos into master, perhaps? Date: Sun, 16 Jan 2022 16:18:11 +0000 Message-ID: References: <83mtjwzwkb.fsf@gnu.org> <87r198ytog.fsf@gnus.org> <87zgnvyb5y.fsf@gnus.org> <924840B9-C416-42E5-A436-D21F16D058AC@acm.org> 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="11868"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Lars Ingebrigtsen , emacs-devel@gnu.org, Eli Zaretskii , Stefan Monnier To: Mattias =?iso-8859-1?Q?Engdeg=E5rd?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Jan 16 17:19:44 2022 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 1n98Fs-0002vZ-00 for ged-emacs-devel@m.gmane-mx.org; Sun, 16 Jan 2022 17:19:44 +0100 Original-Received: from localhost ([::1]:33100 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n98Fq-0006Hb-Ey for ged-emacs-devel@m.gmane-mx.org; Sun, 16 Jan 2022 11:19:42 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:51056) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n98EW-0005ax-6u for emacs-devel@gnu.org; Sun, 16 Jan 2022 11:18:20 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:60979 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1n98ET-0005vg-LF for emacs-devel@gnu.org; Sun, 16 Jan 2022 11:18:19 -0500 Original-Received: (qmail 14078 invoked by uid 3782); 16 Jan 2022 16:18:15 -0000 Original-Received: from acm.muc.de (p2e5d50dc.dip0.t-ipconnect.de [46.93.80.220]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sun, 16 Jan 2022 17:18:15 +0100 Original-Received: (qmail 32571 invoked by uid 1000); 16 Jan 2022 16:18:11 -0000 Content-Disposition: inline In-Reply-To: <924840B9-C416-42E5-A436-D21F16D058AC@acm.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=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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:284833 Archived-At: Hello, Mattias. On Sun, Jan 16, 2022 at 16:50:23 +0100, Mattias Engdegård wrote: > 16 jan. 2022 kl. 16.04 skrev Lars Ingebrigtsen : > > Yes. I've now done a few more realistic non-micro benchmarks -- > > (eww-open-file "/tmp/foo.html") -- and I see no measurable performance > > impact there at all. > The time to run Relint on the Emacs tree is up about 3.0 ± 0.2 %. A > lot of it is spent in reading files and in the regexp engine, neither > of which use `eq` much. It erases some (but not all) of the progress > being made elsewhere. > Micro-benchmarking code using `eq` a lot shows an overhead of about 50 %. Would you clarify, please. 50% of what? The new branch, except whilst compiling, sees EQ extended from two machine instructions to four. In place of CMP ; the two operands. JE , we now have CMP ; the two operands. JE TEST ; symbols-with-pos-enabled. JNE .. More or less. So if the Lisp EQ instruction is going to be matching half the time, there would be an overhead of 50% on just that instruction. Presumably quite a bit less on a whole program. -- Alan Mackenzie (Nuremberg, Germany).