From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Neil Jerram Newsgroups: gmane.lisp.guile.devel Subject: Re: data-crunching in guile Date: Thu, 25 Jun 2009 23:47:47 +0100 Message-ID: <87y6rgszfw.fsf@arudy.ossau.uklinux.net> References: <86r5x891t1.fsf@gnu.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1245970091 29311 80.91.229.12 (25 Jun 2009 22:48:11 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 25 Jun 2009 22:48:11 +0000 (UTC) Cc: Ludovic =?iso-8859-1?Q?Court=E8s?= , guile-devel@gnu.org To: Andy Wingo Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Fri Jun 26 00:48:04 2009 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1MJxjf-0003dr-TC for guile-devel@m.gmane.org; Fri, 26 Jun 2009 00:48:04 +0200 Original-Received: from localhost ([127.0.0.1]:47972 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MJxjf-0001ED-76 for guile-devel@m.gmane.org; Thu, 25 Jun 2009 18:48:03 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MJxjZ-0001E8-Ev for guile-devel@gnu.org; Thu, 25 Jun 2009 18:47:57 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MJxjV-00018R-4P for guile-devel@gnu.org; Thu, 25 Jun 2009 18:47:57 -0400 Original-Received: from [199.232.76.173] (port=32925 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MJxjU-00018A-NG for guile-devel@gnu.org; Thu, 25 Jun 2009 18:47:52 -0400 Original-Received: from mail3.uklinux.net ([80.84.72.33]:48500) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MJxjR-0007hg-Lg; Thu, 25 Jun 2009 18:47:49 -0400 Original-Received: from arudy (host86-152-99-133.range86-152.btcentralplus.com [86.152.99.133]) by mail3.uklinux.net (Postfix) with ESMTP id 39F261F718D; Thu, 25 Jun 2009 23:47:48 +0100 (BST) Original-Received: from arudy.ossau.uklinux.net (arudy [127.0.0.1]) by arudy (Postfix) with ESMTP id 92C5538021; Thu, 25 Jun 2009 23:47:47 +0100 (BST) In-Reply-To: (Andy Wingo's message of "Thu\, 25 Jun 2009 23\:08\:32 +0200") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.4-2.6 X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:8770 Archived-At: Andy Wingo writes: > I don't have Neil's mail open here, but my thought was this: getting a > fast VM is a dark art of feeling and instinct, My feeling is that a VM > is fast if it fits in the CPU's cache: the instruction cache and the > data cache. The data cache means that smaller code is better, hence my > resistance to word-sized instructions. The instruction cache means that > the VM itself should be small -- but if the code for vector ops is all > "at the end" of the VM, then only code that uses vector ops pays for the > increased "cache footprint" of the VM. Thanks, I see now. But presumably even VM code will frequently call out to primitives all over libguile, won't it? I completely agree that small code size can be important for performance, but I doubt that it is the size of the VM on its own that matters. (Or am I still not understanding what you mean?) > But like I say, all this is instinct, which may well be wrong. Me too! Neil