Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754024Ab0AHTMm (ORCPT ); Fri, 8 Jan 2010 14:12:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753903Ab0AHTMl (ORCPT ); Fri, 8 Jan 2010 14:12:41 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53872 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753881Ab0AHTMk (ORCPT ); Fri, 8 Jan 2010 14:12:40 -0500 Date: Fri, 8 Jan 2010 11:11:32 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Christoph Lameter cc: Andi Kleen , Peter Zijlstra , KAMEZAWA Hiroyuki , Minchan Kim , "Paul E. McKenney" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "hugh.dickins" , Nick Piggin , Ingo Molnar Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() In-Reply-To: Message-ID: References: <20100104182429.833180340@chello.nl> <28c262361001042029w4b95f226lf54a3ed6a4291a3b@mail.gmail.com> <20100105134357.4bfb4951.kamezawa.hiroyu@jp.fujitsu.com> <20100105143046.73938ea2.kamezawa.hiroyu@jp.fujitsu.com> <20100105163939.a3f146fb.kamezawa.hiroyu@jp.fujitsu.com> <20100106092212.c8766aa8.kamezawa.hiroyu@jp.fujitsu.com> <20100106115233.5621bd5e.kamezawa.hiroyu@jp.fujitsu.com> <20100106125625.b02c1b3a.kamezawa.hiroyu@jp.fujitsu.com> <1262969610.4244.36.camel@laptop> <87my0omo3n.fsf@basil.nowhere.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1629 Lines: 40 On Fri, 8 Jan 2010, Christoph Lameter wrote: > On Fri, 8 Jan 2010, Andi Kleen wrote: > > > This year's standard server will be more like 24-64 "cpus" > > What will it be? 2 or 4 sockets? I think we can be pretty safe in saying that two sockets is going to be overwhelmingly the more common case. It's simply physics and form factor. It's hard to put four powerful CPU's on one board in any normal form-factor, so when you go from 2->4 sockets, you almost inevitably have to go to rather fancier form-factors (or low-power sockets designed for socket-density rather than multi-core density, which is kind of against the point these days). So often you end up with CPU daughter-cards etc, which involves a lot more design and cost, and no longer fit in standard desktop enclosures for people who want stand-alone servers etc (or even in rack setups if you want local disks too etc). Think about it this way: just four sockets and associated per-socket RAM DIMM's (never mind anything else) take up a _lot_ of space. And you can only make your boards so big before they start having purely machanical issues due to flexing etc. Which is why I suspect that two sockets will be the bulk of the server space for the forseeable future. It's been true before, and multiple memory channels per socket to feed all those cores are just making it even more so. Linus -- 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/