From owner-freebsd-smp Wed Nov 1 16:32:28 2000 Delivered-To: freebsd-smp@freebsd.org Received: from smtp02.primenet.com (smtp02.primenet.com [206.165.6.132]) by hub.freebsd.org (Postfix) with ESMTP id 4F64637B933; Wed, 1 Nov 2000 16:32:26 -0800 (PST) Received: (from daemon@localhost) by smtp02.primenet.com (8.9.3/8.9.3) id RAA06388; Wed, 1 Nov 2000 17:28:40 -0700 (MST) Received: from usr08.primenet.com(206.165.6.208) via SMTP by smtp02.primenet.com, id smtpdAAAy2ayxm; Wed Nov 1 17:28:26 2000 Received: (from tlambert@localhost) by usr08.primenet.com (8.8.5/8.8.5) id RAA10413; Wed, 1 Nov 2000 17:32:05 -0700 (MST) From: Terry Lambert Message-Id: <200011020032.RAA10413@usr08.primenet.com> Subject: Re: HLT To: drosih@rpi.edu (Garance A Drosihn) Date: Thu, 2 Nov 2000 00:32:05 +0000 (GMT) Cc: tlambert@primenet.com (Terry Lambert), msmith@FreeBSD.ORG (Mike Smith), drony@spray.se, freebsd-smp@FreeBSD.ORG In-Reply-To: from "Garance A Drosihn" at Nov 01, 2000 06:43:40 PM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > I don't know the answer to the following question, but does > that comparison take into account cooling costs? Particularly > as one loads up a building with many computers, you realize > you are also buying air conditioners to cool things back down. What are the comparative costs for cooling a factory making the equipment at a higher energy expenditure? If the electricty goes in one end, the heat has to come out somewhere. More energy in = more energy out. I guess there might be a slight skew, since most people aren't dumb enough to try to overclock a factory. 8-). -- a tangent, ignoring the concept of net energy expenditure -- Maybe we would all generate less waste heat if we performed useful computations, since energy not converted into work gets converted into waste heat. So if we all worked on the big important problems, then we would generate no waste heat at all. Heck, we could even hook up a temperature sensor to a CPU, and then run sample problems through it. This would let us know how relatively important the universe thinks solving a particular problem is, since the more important the problem, the less of our energy would come out as waste heat, instead of work. I suspect the universe is worried about its own eventual heat death, since anecdotally, it seems to favor HLT. I think this is backed up by the fact that it would like time to go as slow as possible, to delay this unhappy event, since it also seems, by way of the amount of heat generated, to look with stern disfavor people overclocking their CPU to make the time needed to do computations go by faster. As more anedotal evidence, I offer that my normal body temperature is somewhat depressed from the average, so I must be doing something right. I guess doing transitive closure on all this means that if you find yourself becoming uncomfortably hot, you should kill someone who is overclocking their computer, and the universe may reward you by lowering your body temperature, while the people around you sweat themselves to death... something to remember for next summer. 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