From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: MPS: dangling markers Date: Sat, 29 Jun 2024 14:30:36 -0400 Message-ID: References: <87v81u85hv.fsf@localhost> <87frsx81m2.fsf@localhost> <87cyo180y2.fsf@localhost> <874j9d7zqe.fsf@localhost> <87sewvg6lw.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="7836"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Ihor Radchenko , emacs-devel@gnu.org, Eli Zaretskii , eller.helmut@gmail.com To: Gerd =?windows-1252?Q?M=F6llmann?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Jun 29 20:31:30 2024 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 1sNcrC-0001vX-D9 for ged-emacs-devel@m.gmane-mx.org; Sat, 29 Jun 2024 20:31:30 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sNcqc-0003dc-Jb; Sat, 29 Jun 2024 14:30:54 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sNcqZ-0003dL-TE for emacs-devel@gnu.org; Sat, 29 Jun 2024 14:30:52 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sNcqW-0006UZ-S7; Sat, 29 Jun 2024 14:30:50 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 479BF80452; Sat, 29 Jun 2024 14:30:45 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1719685843; bh=UCwpcdK/WwAjN3lU5KVhao14TZOKsCJnPG6aWNDj+OM=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=LaKxZsA0agIz1RRDCihVGlXsI8dsntSws+xIE9ZTfcsgv6Ft5Ji8VTtFqkEXE+8pZ RQXk945/wRAtmp9hVkJ8CahZMnOngsOyEVSvN23iGYCiTvU/e607XRvmKasFCQPEix c7/Vl27VdVdKW+hV3RA9RstapCBP83+uc7x1Umcog/evgs94w+92LPYR8yOkDDiuUU Bj/lJw2Z3lzpiQVz8jr9I0V9jc90lvOfB6iBjHAvX2+JPw2LR0n7FcA/22QynvpX7g +ehb7JNEn5cQlzwyhkEsiTP6BP6mqOSdsBZak91bFcOSyrB2nvM6MIjBxYjcxhGrJO zFHIb8H2lmSNg== Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id CBE588045E; Sat, 29 Jun 2024 14:30:43 -0400 (EDT) Original-Received: from pastel (unknown [45.72.245.253]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 87DAC120170; Sat, 29 Jun 2024 14:30:43 -0400 (EDT) In-Reply-To: ("Gerd =?windows-1252?Q?M=F6l?= =?windows-1252?Q?lmann=22's?= message of "Sat, 29 Jun 2024 20:12:39 +0200") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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: 2.1.29 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-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:320882 Archived-At: > Can it be that `remove_marker` is called much more often than add_marker? I don't think you can remove a marker before having added it, so it seems rather unlikely. > igc_add_marker (struct buffer *b, struct Lisp_Marker *m) > { > Lisp_Object v = BUF_MARKERS (b); > if (NILP (v)) > v = BUF_MARKERS (b) = alloc_vector_weak (1, Qnil); > > ptrdiff_t i = find_nil_index (v); My guess is that `find_nil_index` almost always scans the buffer until near the end. It should be fairly easy to speed that up by keeping a "pointer" to the last known empty slot, or use the empty slots to "point to each other" to form a free-list. Still doesn't explain why `remove_marker` takes more time on your branch than on `master`, unless we end up keeping significantly larger vectors than the length of the linked-lists used on `master`. Maybe it's because `unchain_marker` often exits early (e.g. maybe it's common that `unchain_marker` is used to delete a marker recently added, so it's near the top of the linked list which ends up behaving a bit like a stack)? Stefan