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: Eager garbage collection Date: Mon, 16 Nov 2020 13:37:19 -0500 Message-ID: References: <87ft5akkjv.fsf@catern.com> <835z65tg48.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="38611"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: sbaugh@catern.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Nov 16 20:12:26 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 1kejvO-0009w7-SY for ged-emacs-devel@m.gmane-mx.org; Mon, 16 Nov 2020 20:12:26 +0100 Original-Received: from localhost ([::1]:37474 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kejvN-0005Bd-Ui for ged-emacs-devel@m.gmane-mx.org; Mon, 16 Nov 2020 14:12:25 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:39166) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kejNV-0000pi-Ju for emacs-devel@gnu.org; Mon, 16 Nov 2020 13:37:25 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:38018) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kejNT-00084Q-7B; Mon, 16 Nov 2020 13:37:24 -0500 Original-Received: from pmg1.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 59689100257; Mon, 16 Nov 2020 13:37:21 -0500 (EST) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id DF436100229; Mon, 16 Nov 2020 13:37:19 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1605551839; bh=E1lnfr3wi1o6W2A8mZaPcbavuvC1UjrEP5GxDxeNCA4=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=ajVopy971RqUCEez9BNaxMbc63LpiPfNNxIb2LIgXSzYTDFsVSQwIoNKBxTO6V6Bw WJwFsfH/pQVrI0txuosxS75Lgptnfvvj3CHr2FrxbriKx5ucvJOMBS4DanMVdNK/kX vzBKY1p52kGKFx271UAA5KxZOlS6pQgq6ahhCtZFgPshkBnylUXk/Azvx4VFcOZqhB Oo7TURtExljWVF6JYCkCSRjDu9DRGwQ979iWn+iJl6/eXcRR5d2qR0ttvTxtb5C7JQ 34OvlC+rpfN4dfwLVjW0JKz6QJYiUabVwPd5NPv5nVIXe1/pzK2ox+Zi+SKoimftCu G5hrc9vRHroHw== Original-Received: from alfajor (unknown [157.52.9.240]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id B23F41203B9; Mon, 16 Nov 2020 13:37:19 -0500 (EST) In-Reply-To: <835z65tg48.fsf@gnu.org> (Eli Zaretskii's message of "Mon, 16 Nov 2020 18:34:47 +0200") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/16 12:36:14 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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: 2.1.23 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:259248 Archived-At: >> This will cause an eager GC right after Emacs goes idle, which can >> happen while the user is actively typing. I think it would be >> preferable to run this from an idle timer to make sure that we run >> during an actual pause of incoming events. Your code effectively uses >> an idle-time of 0, and I'm not sure what idle-time we should >> use instead. >> >> Admittedly, using an idle time of 0 means we start the GC right at the >> beginning of the (potentially short) pause, which also makes it more >> likely that we'll have finished GC before the next event comes in. > > Starting GC immediately when Emacs becomes idle will degrade > responsiveness if there's a lot of garbage, because once GC starts, it > runs to completion no matter what. Indeed. > So maybe this "eager" GC should also be sensitive to the amount of > garbage, in a sense that it should wait more if there's lot of it. The time to do a GC doesn't depend on the amount of garbage so much as the size of the heap, but I think I like your idea. Better yet: keep track of the time that each GC takes and use that as a guide for the idle-time delay. Stefan