Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932200AbWEBLTV (ORCPT ); Tue, 2 May 2006 07:19:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932226AbWEBLTV (ORCPT ); Tue, 2 May 2006 07:19:21 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:38860 "EHLO mx3.mail.elte.hu") by vger.kernel.org with ESMTP id S932200AbWEBLTU (ORCPT ); Tue, 2 May 2006 07:19:20 -0400 Date: Tue, 2 May 2006 13:24:09 +0200 From: Ingo Molnar To: Nick Piggin Cc: blaisorblade@yahoo.it, Andrew Morton , linux-kernel@vger.kernel.org, Linux Memory Management Subject: Re: [patch 00/14] remap_file_pages protection support Message-ID: <20060502112409.GA28159@elte.hu> References: <20060430172953.409399000@zion.home.lan> <4456D5ED.2040202@yahoo.com.au> <4456D85E.6020403@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4456D85E.6020403@yahoo.com.au> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.1 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.1 required=5.9 tests=AWL autolearn=no SpamAssassin version=3.0.3 0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 34 * Nick Piggin wrote: > >Let's try get back to the good old days when people actually reported > >their bugs (togther will *real* numbers) to the mailing lists. That way, > >everybody gets to think about and discuss the problem. > > Speaking of which, let's see some numbers for UML -- performance and > memory. I don't doubt your claims, but I (and others) would be > interested to see. firstly, thanks for the review feedback! originally i tested this feature with some minimal amount of RAM simulated by UML 128MB or so. That's just 32 thousand pages, but still the improvement was massive: context-switch times in UML were cut in half or more. Process-creation times improved 10-fold. With this feature included I accidentally (for the first time ever!) confused an UML shell prompt with a real shell prompt. (before that UML was so slow [even in "skas mode"] that you'd immediately notice it by the shell's behavior) the 'have 1 vma instead of 32,000 vmas' thing is a really, really big plus. It makes UML comparable to Xen, in rough terms of basic VM design. Now imagine a somewhat larger setup - 16 GB RAM UML instance with 4 million vmas per UML process ... Frankly, without sys_remap_file_pages_prot() the UML design is still somewhat of a toy. Ingo - 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/