From owner-freebsd-smp Tue Dec 15 17:47:16 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA02779 for freebsd-smp-outgoing; Tue, 15 Dec 1998 17:47:16 -0800 (PST) (envelope-from owner-freebsd-smp@FreeBSD.ORG) Received: from Chuska.ConSys.COM (Chuska.ConSys.COM [209.141.107.5]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA02774 for ; Tue, 15 Dec 1998 17:47:14 -0800 (PST) (envelope-from rcarter@psf.Pinyon.ORG) Received: from psf.Pinyon.ORG (ip-17-196.prc.primenet.com [207.218.17.196]) by Chuska.ConSys.COM (8.9.1/8.9.1) with ESMTP id SAA17893; Tue, 15 Dec 1998 18:47:07 -0700 (MST) Received: from psf.Pinyon.ORG (localhost [127.0.0.1]) by psf.Pinyon.ORG (8.9.1/8.8.7) with ESMTP id SAA03907; Tue, 15 Dec 1998 18:44:15 -0700 (MST) Message-Id: <199812160144.SAA03907@psf.Pinyon.ORG> X-Mailer: exmh version 2.0.2 2/24/98 To: Terry Lambert cc: smp@FreeBSD.ORG Subject: Re: Pthreads and SMP In-reply-to: Your message of "Tue, 15 Dec 1998 07:32:54 GMT." <199812150732.AAA12768@usr06.primenet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 15 Dec 1998 18:44:14 -0700 From: "Russell L. Carter" Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > The problem space mappable using SMP is not trivially small, but > it's a hell of a lot smaller than the problem space that can be > mapped with 32 times the computations per clock cycle on a linear > uniprocessor. . I've absorbed (maybe reflected is more accurate) considerable netnoise flack from pointing out that the problem space for distributed memory parallel systems is considerably (even exponentially) smaller than that for SMP. The reason is the same as for SMP vs. uniprocessor. If you are unfortunate to be living in the real world of memory with hierarchies of different access speeds and don't have nearly complete locality for memory references for each and every parallelizable task you are (nearly always) hosed. Wait a minute! Did I just agree with Terry? :-) Russell > > Terry Lambert > terry@lambert.org > --- > Any opinions in this posting are my own and not those of my present > or previous employers. > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-smp" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message