From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: t and nil in pure memory? Date: Wed, 18 Nov 2009 20:01:33 -0500 Message-ID: References: <200911112023.nABKNrH6023933@godzilla.ics.uci.edu> <87pr7oxieq.fsf@freebits.de> <200911130524.nAD5O5uu009102@godzilla.ics.uci.edu> <200911152108.nAFL8IBl006966@godzilla.ics.uci.edu> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1258592514 5728 80.91.229.12 (19 Nov 2009 01:01:54 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 19 Nov 2009 01:01:54 +0000 (UTC) Cc: Emacs development discussions To: Ken Raeburn Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Nov 19 02:01:47 2009 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1NAvP8-0006nf-F9 for ged-emacs-devel@m.gmane.org; Thu, 19 Nov 2009 02:01:46 +0100 Original-Received: from localhost ([127.0.0.1]:59644 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NAvP7-0001yW-GX for ged-emacs-devel@m.gmane.org; Wed, 18 Nov 2009 20:01:45 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NAvP2-0001x2-3r for emacs-devel@gnu.org; Wed, 18 Nov 2009 20:01:40 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NAvOx-0001t2-0a for emacs-devel@gnu.org; Wed, 18 Nov 2009 20:01:39 -0500 Original-Received: from [199.232.76.173] (port=53018 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NAvOw-0001sz-UU for emacs-devel@gnu.org; Wed, 18 Nov 2009 20:01:34 -0500 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.181]:16152 helo=ironport2-out.pppoe.ca) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NAvOw-0007bw-DT for emacs-devel@gnu.org; Wed, 18 Nov 2009 20:01:34 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApsEABMoBEvO+IIa/2dsb2JhbACBTdc6hDsEiVc X-IronPort-AV: E=Sophos;i="4.44,767,1249272000"; d="scan'208";a="49632106" Original-Received: from 206-248-130-26.dsl.teksavvy.com (HELO pastel.home) ([206.248.130.26]) by ironport2-out.pppoe.ca with ESMTP; 18 Nov 2009 20:01:33 -0500 Original-Received: by pastel.home (Postfix, from userid 20848) id 42C548774; Wed, 18 Nov 2009 20:01:33 -0500 (EST) In-Reply-To: (Ken Raeburn's message of "Wed, 18 Nov 2009 13:53:28 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) X-detected-operating-system: by monty-python.gnu.org: Genre and OS details not recognized. X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:117223 Archived-At: > There are lots of changes, major or minor, that might be worth exploring. > Prefetching, putting mark bits on different words or pages, tri-color > schemes, incremental marking, generational GC, etc., etc. But maybe we > should also consider a more drastic change: Use Hans Boehm's GC library. It's definitely worth exploring. IIRC the main problem with it was how to get the necessary pointer-weakness where we expect it (hash-tables, markers, undo-lists, and a couple others I can't remember), and of course add the relevant hooks to get back the GC-precision we currently enjoy. Oh, and of course, we'd need to compare the performance (memory use and CPU use, mostly) to make sure it doesn't get worse. I'd expect the memory use to go up slightly, not sure about the performance. It likely would improve our vector-allocation performance (which currently sucks). Also we'd need to decide what to do about the platforms not supported by the Boehm GC. Stefan