From owner-freebsd-arch Thu Jun 27 14:28:31 2002 Delivered-To: freebsd-arch@freebsd.org Received: from pintail.mail.pas.earthlink.net (pintail.mail.pas.earthlink.net [207.217.120.122]) by hub.freebsd.org (Postfix) with ESMTP id 7FB2E37B400; Thu, 27 Jun 2002 14:28:26 -0700 (PDT) Received: from pool0530.cvx21-bradley.dialup.earthlink.net ([209.179.194.20] helo=mindspring.com) by pintail.mail.pas.earthlink.net with esmtp (Exim 3.33 #2) id 17NgoR-0003y0-00; Thu, 27 Jun 2002 14:28:23 -0700 Message-ID: <3D1B834E.70573706@mindspring.com> Date: Thu, 27 Jun 2002 14:27:42 -0700 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Jonathan Lemon Cc: Julian Elischer , Greg 'groggy' Lehey , arch@FreeBSD.ORG Subject: Re: Larry McVoy's slides on cache coherent clusters References: <3D1B7391.38F10284@mindspring.com> <20020627152602.A1020@prism.flugsvamp.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Jonathan Lemon wrote: > On Thu, Jun 27, 2002 at 01:20:33PM -0700, Terry Lambert wrote: > > My personal target rests above NUMA, where there are relatively > > glacially slow communications channels, compared to CPU speed; > > this is basically the environment in which, for example, you > > have literally millions of processors operating from incomplete > > information with potentially lossy communications channels. > > A.K.A. "The Internet". Actually, a worse communication vs. CPU speed ratio than that, eventually. There are a couple of problems that can only be solved with an architecture that assumes a progression of the ratio. I think Larry persuasively demonstrates that there is a hierarchy in communications channels vs. CPU speed that is not accounted for in most OS design. My scale ("Lambert's Interconnection Scale"? 8-)) would be: ---- ---- ---------- ----------------------------------- CPUS DIES SEPERATION NAME ---- ---- ---------- ----------------------------------- 1 1 0 Processing (8-)) N 1 0 SMT N M 1 SMP N M 2 NUMA N M 3 Distributed (full information) N M 4 Distributed (partial information) N M 5 Distributed (partial functionality) ---- ---- ---------- ----------------------------------- The hardware DES breaker that was built as a proof of concept was purpose-built hardware with a seperation of 2. The 65,536 processor machine that Good Year built for modelling laminar airflow on the full shuttle airframe was purpose built hardware with a seperation of 2. So were most of the Connection Machine series from Thinking Machines, Inc.. SETI@Home is a purpose-built machine with a seperation of 3, and so are the protein folding and crypto-breaking and similar systems. The Javalin research project was a virtual machine general purpose computing platform with a seperation of 3. One of the things that Kazaa is attempting is to build a general purpose computing platform -- a real machine -- with a seperation of 3 (whether they realize this or not is another matter). Larry's presentation claims (in slide 11) that the traditional MP approach has been to "build a solution, and scale it up", e.g.: ``We're at 2, can you get to 4?'' ``We're at 4, can you get to 8?'' Etc. And then he asks: ``Can you go 3 orders of magnitude farther?'' Which is maybe the wrong question; it pegs your initial position farther out on the incrementalism scale, but doesn't answer the question of how to get from N to N+1 for an arbitrary N. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message