From owner-freebsd-threads@FreeBSD.ORG Thu Nov 6 07:16:41 2003 Return-Path: Delivered-To: freebsd-threads@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AA11516A4CE for ; Thu, 6 Nov 2003 07:16:41 -0800 (PST) Received: from mail.pcnet.com (mail.pcnet.com [204.213.232.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id EEF8C43FAF for ; Thu, 6 Nov 2003 07:16:40 -0800 (PST) (envelope-from eischen@vigrid.com) Received: from mail.pcnet.com (mail.pcnet.com [204.213.232.4]) by mail.pcnet.com (8.12.10/8.12.1) with ESMTP id hA6FGe1G010769 for ; Thu, 6 Nov 2003 10:16:40 -0500 (EST) Date: Thu, 6 Nov 2003 10:16:40 -0500 (EST) From: Daniel Eischen X-Sender: eischen@pcnet5.pcnet.com To: threads@freebsd.org Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Subject: Butenhof on Solaris 1:1 vs M:N X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 Nov 2003 15:16:41 -0000 I found this interesting take by David Butenhof on Sun's choice of the 1:1 model over the M:N model: http://groups.google.com/groups?q=M+x+N+group:comp.programming.threads&hl=en&lr=&ie=UTF-8&oe=UTF-8&scoring=d&selm=3f1e86d9%40usenet01.boi.hp.com&rnum=3 "Yes, it is hard to get M:N working right, though there are real advantages. (System Software development is not generally dedicated to the principle of avoiding "hard" problems, after all.) But the history of Sun's trouble with M:N isn't nearly as much technical as political. Even when developers tried to address design problems, they weren't allowed. So, yes, giving up on M:N probably was the best course, for Sun. M:N isn't something that can be done halfway -- you either commit to the whole thing and follow through, or you're better off not trying. Unlike Solaris, the Tru64 UNIX M:N scheduling model was actually designed to work, and does. It (like all else) isn't perfect, but it scales, it supports detailed and effective debugging, and it's cleanly and deeply integrated with the kernel." -- Dan Eischen