Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761395AbXEKQwM (ORCPT ); Fri, 11 May 2007 12:52:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757075AbXEKQv7 (ORCPT ); Fri, 11 May 2007 12:51:59 -0400 Received: from smtp1.linux-foundation.org ([65.172.181.25]:59685 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384AbXEKQv6 (ORCPT ); Fri, 11 May 2007 12:51:58 -0400 Date: Fri, 11 May 2007 09:50:10 -0700 (PDT) From: Linus Torvalds To: Pavel Machek cc: 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, Willy Tarreau , Gene Heskett , Mark Lord , Zach Carter , buddabrod Subject: Re: [patch] CFS scheduler, -v8 In-Reply-To: <20070510130954.GC4052@ucw.cz> Message-ID: References: <463854F3.3020403@linux.vnet.ibm.com> <20070502100545.GA6857@elte.hu> <46386F2B.9050307@linux.vnet.ibm.com> <20070502111742.GA18132@elte.hu> <20070506082911.GA32644@elte.hu> <463FC5D8.2090502@bigpond.net.au> <20070510130954.GC4052@ucw.cz> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-1463790079-762656802-1178902213=:3986" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2147 Lines: 48 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---1463790079-762656802-1178902213=:3986 Content-Type: TEXT/PLAIN; charset=iso-8859-15 Content-Transfer-Encoding: 8BIT On Thu, 10 May 2007, Pavel Machek wrote: > > 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%). Of course, all the other components have a MTBF too (and I'd generally expect a power supply component to fail long before the CPU does). And yes, some machines will last for decades. But I suspect we've all heard of machines that just don't work reliably any more. Linus ---1463790079-762656802-1178902213=:3986-- - 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/