Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761997AbXEKTjd (ORCPT ); Fri, 11 May 2007 15:39:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758807AbXEKTjY (ORCPT ); Fri, 11 May 2007 15:39:24 -0400 Received: from 1wt.eu ([62.212.114.60]:2578 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758368AbXEKTjX (ORCPT ); Fri, 11 May 2007 15:39:23 -0400 Date: Fri, 11 May 2007 21:37:51 +0200 From: Willy Tarreau To: Pavel Machek Cc: Linus Torvalds , Peter Williams , Esben Nielsen , Ingo Molnar , Balbir Singh , linux-kernel@vger.kernel.org, Andrew Morton , Con Kolivas , Nick Piggin , Mike Galbraith , Arjan van de Ven , Thomas Gleixner , caglar@pardus.org.tr, Gene Heskett , Mark Lord , Zach Carter , buddabrod Subject: Re: [patch] CFS scheduler, -v8 Message-ID: <20070511193751.GC20383@1wt.eu> References: <20070502111742.GA18132@elte.hu> <20070506082911.GA32644@elte.hu> <463FC5D8.2090502@bigpond.net.au> <20070510130954.GC4052@ucw.cz> <20070511191824.GA7135@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070511191824.GA7135@ucw.cz> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2910 Lines: 65 On Fri, May 11, 2007 at 07:18:25PM +0000, Pavel Machek wrote: > Hi! > > > > Also notice that current cpus were not designed to work 300 years. > > > When we have hw designed for 50 years+, we can start to worry. > > > > Indeed. CPU manufacturers don't seem to talk about it very much, and > > searching for it with google on intel.com comes up with > > > > The failure rate and Mean Time Between Failure (MTBF) data is not > > currently available on our website. You may contact Intel? > > Customer Support for this information. > > > > which seems to be just a fancy way of saying "we don't actually want to > > talk about it". Probably not because it's actually all that bad, but > > simply because people don't think about it, and there's no reason a CPU > > manufacturer would *want* people to think about it. > > > > But if you wondered why server CPU's usually run at a lower frequency, > > it's because of MTBF issues. I think a desktop CPU is usually specced to > > run for 5 years (and that's expecting that it's turned off or at least > > idle much of the time), while a server CPU is expected to last longer and > > be active a much bigger percentage of time. > > > > ("Active" == "heat" == "more damage due to atom migration etc". Which is > > part of why you're not supposed to overclock stuff: it may well work well > > for you, but for all you know it will cut your expected CPU life by 90%). > > Actually, when I talked with AMD, they told me that cpus should last > 10 years *at their max specced temperature*... which is 95Celsius. So > overclocking is not that evil, according to my info. I tend to believe that. I've slowed down the FANs on my dual-athlon XP to silent them, and I found the system to be (apparently) stable till 96 deg Celsius with FANs unplugged. So I regulated them in order to maintain a temperature below 90 deg for a safety margin, and they seem to be as happy as my ears. They've been like that for the last 3-4 years, I don't remember. On a related note, older technology is less sensible. My old VAX VLC4000 from 1991 which received a small heatsink in exchange for its noisy fans is still doing well in an closed place. I'm more worried for the EPROMs which store the boot code. Also, I think that the RS6000 processed at half-micron which run the Mars rovers might run for hundreds of years at 30 MHz. > (That would mean way more than 10 years if you use your cpu > 'normally'.) > > But I guess capacitors from cpu power supply will hate you running cpu > at 95C... even at 60, many of them die within a few years. Bu I think we're "slightly" off-topic now... > Pavel Cheers Willy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/