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: Larger GC thresholds for non-interactive Emacs Date: Thu, 23 Jun 2022 18:12:19 -0400 Message-ID: References: <87r13up587.fsf@localhost> <83o7yyur0l.fsf@gnu.org> <87leu2p3nu.fsf@localhost> <83leu2uewn.fsf@gnu.org> <87r13qv701.fsf@localhost> <83bkuursya.fsf@gnu.org> <87h74l9jk8.fsf@localhost> <83bkutqb3z.fsf@gnu.org> <9778F176-E724-4E61-B0FB-327BCDD316C0@acm.org> <87sfo4epeo.fsf@localhost> <87bkurrc5e.fsf@localhost> <87bkur72b7.fsf@gnus.org> <874k0j40e7.fsf@gnus.org> <874k0hxb0g.fsf@localhost> <87wndb34qj.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="2493"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Lars Ingebrigtsen , Mattias =?windows-1252?Q?Engdeg?= =?windows-1252?Q?=E5rd?= , Eli Zaretskii , Tim Cross , rms@gnu.org, Alan Mackenzie , emacs-devel To: Ihor Radchenko Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Jun 24 00:14:04 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 1o4V5Q-0000Ro-2T for ged-emacs-devel@m.gmane-mx.org; Fri, 24 Jun 2022 00:14:04 +0200 Original-Received: from localhost ([::1]:42416 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o4V5O-0004PJ-9G for ged-emacs-devel@m.gmane-mx.org; Thu, 23 Jun 2022 18:14:02 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33914) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o4V3u-0003Xx-K8 for emacs-devel@gnu.org; Thu, 23 Jun 2022 18:12:30 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:29821) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o4V3r-0004Ut-R0; Thu, 23 Jun 2022 18:12:29 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id AB667441D9A; Thu, 23 Jun 2022 18:12:25 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 69BC1441D94; Thu, 23 Jun 2022 18:12:24 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1656022344; bh=v+gNozPY2qelCsodUXBLDHtK1D4bZCEFVB8L3vanu/Y=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=m/ds7sA+OXmvmSEv/khnF8s61Uit59iaJP2F97062XBH5IOGfwkeMJT+bEiLZQo2C JUXahGZ6w6SZh08RMyJKxOKd28RJmwa4gmGKjeSYqg5qApewca5G76DL98sJhgJtQX Y871lJmSKWkhDczSRFkDU1WtIUUVS7O0jr7AOLUPOHEap9i6m1blys2NbdBDndhnnM pWzaa/zLIQHp+1A4Km8IFPiP4ACCf7l/iODr/d+6e1E+yt93R1uJ9IjyjY4hl23f34 ZKNfLAT1Y6vvu7oGkVX4EHhvVU4qfqk2jc45KYi+k3WGEJSRPA2lPOBMh5gN3WB+mU Pb35p0sguRYfA== Original-Received: from alfajor (196.214.25.93.rev.sfr.net [93.25.214.196]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id A30051202AF; Thu, 23 Jun 2022 18:12:22 -0400 (EDT) In-Reply-To: <87wndb34qj.fsf@localhost> (Ihor Radchenko's message of "Mon, 20 Jun 2022 20:21:24 +0800") 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, T_SCC_BODY_TEXT_LINE=-0.01 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" Xref: news.gmane.io gmane.emacs.devel:291545 Archived-At: >> The difference between the two cases is that when you have half of the >> heap made up of dead objects, there's a higher probability that some of >> those objects are clustered such that they make up a few complete >> 16kB blocks, whereas when only the dead objects represent only 10% of >> the heap, almost all 16kB blocks will contain a mis of dead and live >> objects and hence can't be returned to the malloc library. > > I am again confused. > Does what you say imply that frequent GC with small threshold is not > good because it will have less dead objects and have higher chance of > fragmentation? Not at all. The general rule of thumb is: the sooner you recover free space, the better you can avoid fragmentation. Stefan