From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" Newsgroups: gmane.emacs.bugs Subject: bug#68244: hash-table improvements Date: Sun, 07 Jan 2024 14:10:29 -0500 Message-ID: References: <170438379722.3921.9312235725296561206@vcs2.savannah.gnu.org> <20240104155642.B4A99C00344@vcs2.savannah.gnu.org> <8d49ebdc-9da7-4e70-a080-d8e892b980b6@gutov.dev> <08314177-5AE9-4352-94A0-641830B4094D@gmail.com> Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28245"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Dmitry Gutov , Eli Zaretskii , 68244@debbugs.gnu.org To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jan 07 20:11:20 2024 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1rMYYJ-0007AQ-Sx for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 07 Jan 2024 20:11:20 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rMYXy-0004Id-Ax; Sun, 07 Jan 2024 14:10:58 -0500 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 1rMYXw-0004IU-UM for bug-gnu-emacs@gnu.org; Sun, 07 Jan 2024 14:10:56 -0500 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rMYXw-0006oo-MO for bug-gnu-emacs@gnu.org; Sun, 07 Jan 2024 14:10:56 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1rMYY1-0002xK-Vo for bug-gnu-emacs@gnu.org; Sun, 07 Jan 2024 14:11:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 07 Jan 2024 19:11:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 68244 X-GNU-PR-Package: emacs Original-Received: via spool by 68244-submit@debbugs.gnu.org id=B68244.170465464511294 (code B ref 68244); Sun, 07 Jan 2024 19:11:01 +0000 Original-Received: (at 68244) by debbugs.gnu.org; 7 Jan 2024 19:10:45 +0000 Original-Received: from localhost ([127.0.0.1]:33886 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rMYXl-0002w6-Bk for submit@debbugs.gnu.org; Sun, 07 Jan 2024 14:10:45 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:24924) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rMYXj-0002vt-GX for 68244@debbugs.gnu.org; Sun, 07 Jan 2024 14:10:44 -0500 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 61DBB80A90; Sun, 7 Jan 2024 14:10:32 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1704654631; bh=DRwPPaWKhV6kYoZkcQcNXU+F3gqFF2Q1InDUNtGkh/Q=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=e3+mETk0VNm2D6UP3SJM6jwB2Y0tUkq4/CPfocfLJb62FVQeu/fHB1Snr9kWoxZTg G37RWDuMHNgfiHAfBK5B9SKJBptKtZ+CD03gW7G0WDBpt0F1DAToVF7V1IikpgM6QM b45FxJSZKeR1oakJN1kCaf1Qmof1qsxR2w/8yqOhEs3C+TGPqzq6Ol8Ktv1dhF38tT 6NOax5gXO+sG9lAcdq1SPOAJuAujuCCe3tFyW1iP7BV9ZiJtd9W6iZYmMwbN/2b2n8 EFqA7eA5WLHyOE/KDLAN2zVEdRJm/qQODOodjTodj2DFFcGemQyKj1QAazZmkXN8mw aBRAzZ46sQcUg== Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 7FD7080946; Sun, 7 Jan 2024 14:10:31 -0500 (EST) Original-Received: from milanesa (65-110-221-238.cpe.pppoe.ca [65.110.221.238]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 4BD9E12062F; Sun, 7 Jan 2024 14:10:31 -0500 (EST) In-Reply-To: ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Sun, 7 Jan 2024 19:36:17 +0100") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:277524 Archived-At: > I've pushed two new changes: a correction to the GC accounting for the > ancillary hash-table vectors, and a rather more interesting change to the > hash table range reduction. It now uses a Knuth multiplicative method > instead of the expensive remainder, so the index is now always a power of > 2 in size. The change gives good results for small tables but less so for big ones. I don't have a good intuition for why that would be: none of the operations directly involved seem to be more costly for large tables, so my best guess is that it leads to more collisions somehow, tho I don't have a good idea about why that would be. Stefan