Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756621AbZCDRiz (ORCPT ); Wed, 4 Mar 2009 12:38:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753975AbZCDRiq (ORCPT ); Wed, 4 Mar 2009 12:38:46 -0500 Received: from gw.goop.org ([64.81.55.164]:53631 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753948AbZCDRip (ORCPT ); Wed, 4 Mar 2009 12:38:45 -0500 Message-ID: <49AEBCA2.8020307@goop.org> Date: Wed, 04 Mar 2009 09:38:42 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Anthony Liguori CC: Nick Piggin , Xen-devel , Andrew Morton , the arch/x86 maintainers , Linux Kernel Mailing List , "H. Peter Anvin" Subject: Re: [PATCH] xen: core dom0 support References: <1235786365-17744-1-git-send-email-jeremy@goop.org> <200902282309.07576.nickpiggin@yahoo.com.au> <49AB19E1.4050604@goop.org> <200903021737.24903.nickpiggin@yahoo.com.au> <49AB9336.7010103@goop.org> <49AEBB8C.2000405@codemonkey.ws> In-Reply-To: <49AEBB8C.2000405@codemonkey.ws> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1159 Lines: 30 Anthony Liguori wrote: > Jeremy Fitzhardinge wrote: >> Nick Piggin wrote: > >> It really depends on the workload. There's three cases to consider: >> software shadow pagetables, hardware nested pagetables, and Xen >> direct pagetables. Even now, Xen's (highly optimised) shadow >> pagetable code generally out-performs modern nested pagetables, at >> least when running Windows (for which that code was most heavily tuned). > > Can you point to benchmarks? I have a hard time believing this. Erm, not that I know of off-hand. I don't really have any interest in Windows performance, so I'm reduced to repeating (highly reliable) Xen Summit corridor chat. > How can shadow paging beat nested paging assuming the presence of > large pages? I think large pages do turn the tables, and its close to parity with shadow with 4k pages on recent cpus. But see above for reliability on that info. J -- 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/