From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: tags in the 3 lowest bits Date: 20 Nov 2003 09:52:19 -0500 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: References: NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1069340247 31149 80.91.224.253 (20 Nov 2003 14:57:27 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Thu, 20 Nov 2003 14:57:27 +0000 (UTC) Cc: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Thu Nov 20 15:57:24 2003 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1AMqFI-0004sh-00 for ; Thu, 20 Nov 2003 15:57:24 +0100 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.35 #1 (Debian)) id 1AMqFI-0006Jt-00 for ; Thu, 20 Nov 2003 15:57:24 +0100 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1AMr9v-0006xK-Au for emacs-devel@quimby.gnus.org; Thu, 20 Nov 2003 10:55:55 -0500 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.24) id 1AMr9C-0006gd-8E for emacs-devel@gnu.org; Thu, 20 Nov 2003 10:55:10 -0500 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.24) id 1AMr8d-0006Us-U1 for emacs-devel@gnu.org; Thu, 20 Nov 2003 10:55:07 -0500 Original-Received: from [132.204.24.67] (helo=mercure.iro.umontreal.ca) by monty-python.gnu.org with esmtp (Exim 4.24) id 1AMr7v-0006P1-8J for emacs-devel@gnu.org; Thu, 20 Nov 2003 10:53:51 -0500 Original-Received: from vor.iro.umontreal.ca (vor.iro.umontreal.ca [132.204.24.42]) by mercure.iro.umontreal.ca (8.12.9/8.12.9) with ESMTP id hAKEqKbj013890; Thu, 20 Nov 2003 09:52:20 -0500 Original-Received: by vor.iro.umontreal.ca (Postfix, from userid 20848) id E844F3C63E; Thu, 20 Nov 2003 09:52:19 -0500 (EST) Original-To: storm@cua.dk (Kim F. Storm) In-Reply-To: Original-Lines: 15 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 X-DIRO-MailScanner: Found to be clean X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.2 Precedence: list List-Id: Emacs development discussions. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:17967 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:17967 > We could wrap malloc and free on such systems to force 8 byte alignment like > this (it's a little costly in memory, but no big deal): The cost is zero for cons cells and floats (which are already wrapped to ensure alignment, for other reasons), it's negligible for strings, markers, and symbols, but it's a bit heavy for small arrays. OTOH, small arrays are already inefficient (because each array, no matter how small, is added to the memory-map (a binary tree) used for conservative stack marking). So maybe we should begin by changing the handling of small arrays (similar to what is done for strings, although I'm not quite sure what it would look like). Stefan