From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: =?utf-8?Q?=C3=93scar_Fuentes?= Newsgroups: gmane.emacs.devel Subject: Re: Time to merge scratch/correct-warning-pos into master, perhaps? Date: Mon, 21 Feb 2022 15:55:28 +0100 Message-ID: <87fsocjmlb.fsf@telefonica.net> References: <83v8xt20db.fsf@gnu.org> <83ee4gyzrh.fsf@gnu.org> <83v8xryh4d.fsf@gnu.org> <831qzyzt5t.fsf@gnu.org> <874k4u92gp.fsf@randomsample> <87o831jcgf.fsf@telefonica.net> <8335kcx5di.fsf@gnu.org> <87k0dokgpi.fsf@telefonica.net> <83wnhov2is.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="3751"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) To: emacs-devel@gnu.org Cancel-Lock: sha1:nyU39KJ/pBMJZ/qcMDhCWPjlASM= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Feb 21 15:58:55 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 1nMA9O-0000qk-G4 for ged-emacs-devel@m.gmane-mx.org; Mon, 21 Feb 2022 15:58:54 +0100 Original-Received: from localhost ([::1]:53606 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nMA9N-0007MV-KQ for ged-emacs-devel@m.gmane-mx.org; Mon, 21 Feb 2022 09:58:53 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:37390) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nMA6H-0005Pj-6L for emacs-devel@gnu.org; Mon, 21 Feb 2022 09:55:42 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]:58842) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nMA6F-0007wk-CN for emacs-devel@gnu.org; Mon, 21 Feb 2022 09:55:40 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1nMA6D-00074R-G7 for emacs-devel@gnu.org; Mon, 21 Feb 2022 15:55:37 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no 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:286565 Archived-At: Eli Zaretskii writes: >> >> If you want to know the impact of such a change, the correct method is >> >> to measure representative instances of real-world cases. >> > >> > We already did that. We now want to understand _why_ the new version >> > is slower, and then try making it faster. >> >> Then I suggest to use Valgrind for collecting performance data at the >> machine instruction level > > AFAIK, Perf is fully capable of collecting performance data on this > level. Perf is a sampling profiler and that makes very tricky to get reliable data for a tiny piece of code within a large application. > So what will Valgrind gain us, except the need to battle the known > problems when running Emacs under Valgrind? Valgrind emulates each instruction and its context (L1/L2 cache misses, etc.) That's why Valgrind is two orders of magnitude slower than Perf (and it accounts for a good chunk of the "patience" requirement I mentioned on my previous message.) Profiling Emacs with Valgrind should not pose problems, AFAIK.