Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757111AbXKMAms (ORCPT ); Mon, 12 Nov 2007 19:42:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752779AbXKMAmj (ORCPT ); Mon, 12 Nov 2007 19:42:39 -0500 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:45123 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751029AbXKMAmi (ORCPT ); Mon, 12 Nov 2007 19:42:38 -0500 Date: Mon, 12 Nov 2007 16:42:37 -0800 (PST) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Andi Kleen cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Andy Whitcroft Subject: Re: x86_64: Make sparsemem/vmemmap the default memory model In-Reply-To: <200711130059.34346.ak@suse.de> Message-ID: References: <200711130059.34346.ak@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2388 Lines: 75 On Tue, 13 Nov 2007, Andi Kleen wrote: > On Tuesday 13 November 2007 00:52:14 Christoph Lameter wrote: > > Use sparsemem as the only memory model for UP, SMP and NUMA. > > > > Measurements indicate that DISCONTIGMEM has a higher > > overhead than sparsemem. And FLATMEMs benefits are minimal. So I think its > > best to simply standardize on sparsemem. > > How about the memory overhead? Is it the same too? > And code size vs flatmem? SMP Sparsemem ------------- Kernel size: text data bss dec hex filename 3849268 397739 1264856 5511863 541ab7 vmlinux total used free shared buffers cached Mem: 8242252 41164 8201088 0 352 11512 -/+ buffers/cache: 29300 8212952 Swap: 9775512 0 9775512 SMP Flatmem ----------- Kernel size: text data bss dec hex filename 3844612 397739 1264536 5506887 540747 vmlinux So 4.5k growth in text size vs. FLATMEM. total used free shared buffers cached Mem: 8244052 40544 8203508 0 352 11484 -/+ buffers/cache: 28708 8215344 2k growth in overall memory use after boot. NUMA discontig: text data bss dec hex filename 3888124 470659 1276504 5635287 55fcd7 vmlinux total used free shared buffers cached Mem: 8256256 56908 8199348 0 352 11496 -/+ buffers/cache: 45060 8211196 Swap: 9775512 0 9775512 NUMA sparse: text data bss dec hex filename 3896428 470659 1276824 5643911 561e87 vmlinux 8k text growth. Given that we fully inline virt_to_page and friends now that is rather good. total used free shared buffers cached Mem: 8264720 57240 8207480 0 352 11516 -/+ buffers/cache: 45372 8219348 Swap: 9775512 0 9775512 Hmmm... More memory free? How did that happen? More pages cached for some reason. The total available memory is increased by 8k. - 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/