Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261326AbUDHXWS (ORCPT ); Thu, 8 Apr 2004 19:22:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261689AbUDHXWS (ORCPT ); Thu, 8 Apr 2004 19:22:18 -0400 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:19921 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S261326AbUDHXWQ (ORCPT ); Thu, 8 Apr 2004 19:22:16 -0400 Date: Fri, 9 Apr 2004 01:22:15 +0200 From: Andrea Arcangeli To: "Martin J. Bligh" Cc: linux-kernel@vger.kernel.org Subject: Re: -mmX 4G patches feedback [numbers: how much performance impact] Message-ID: <20040408232215.GY31667@dualathlon.random> References: <20040407230140.GT26888@dualathlon.random> <29510000.1081380104@flay> <20040407231806.GV26888@dualathlon.random> <33900000.1081380891@flay> <20040408001845.GX26888@dualathlon.random> <1479132704.1081405456@[10.10.2.4]> <20040408215946.GU31667@dualathlon.random> <29690000.1081462791@flay> <20040408221915.GV31667@dualathlon.random> <32730000.1081466048@flay> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <32730000.1081466048@flay> User-Agent: Mutt/1.4.1i X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1368 Lines: 27 On Thu, Apr 08, 2004 at 04:14:08PM -0700, Martin J. Bligh wrote: > Me confused. Are you saying it's worse compared to pte_highmem? or to > shoving ptes in lowmem? worse than pte_highmem if booting with mem=800m > Ah. You're worried about the distro situation, where PTE_HIGHMEM would > be turned on for a non-highmem machine, right? Makes more sense I guess. it's not just a distro situation, it's about not having to recompile the kernel for every machine I own, even gentoo has an option to have a compile server in the network that build packages and you install the binaries from it, so there must be some value in being able to share a binary on more than one machine (this is especially true for me since I upgrade kernel quite fast). it's not just about non-highmem machines, on 1G/2G boxes the probability that pte-highmem cause you any slowdown is an order of magnitude smaller than on a 32G machine (where ptes should never hit lowmem or it means my classzone lowmem_reserve_ratio algorithms have not yet been ported to 2.6) with your model you'd have no way to boost when you are lucky to get a lowmem page. - 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/