Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757090AbYF1Kwy (ORCPT ); Sat, 28 Jun 2008 06:52:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754937AbYF1Kwn (ORCPT ); Sat, 28 Jun 2008 06:52:43 -0400 Received: from 8bytes.org ([88.198.83.132]:60379 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754585AbYF1Kwl (ORCPT ); Sat, 28 Jun 2008 06:52:41 -0400 Date: Sat, 28 Jun 2008 12:52:40 +0200 From: Joerg Roedel To: Andi Kleen Cc: Muli Ben-Yehuda , Adrian Bunk , Joerg Roedel , tglx@linutronix.de, mingo@redhat.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, bhavna.sarathy@amd.com, Sebastian.Biemueller@amd.com, robert.richter@amd.com Subject: Re: [PATCH 01/34] AMD IOMMU: add Kconfig entry Message-ID: <20080628105240.GI10197@8bytes.org> References: <1214508490-29683-1-git-send-email-joerg.roedel@amd.com> <1214508490-29683-2-git-send-email-joerg.roedel@amd.com> <20080627142558.GG18644@cs181140183.pp.htv.fi> <878wwrq6im.fsf@basil.nowhere.org> <20080627163945.GA26130@il.ibm.com> <20080627165430.GD10197@8bytes.org> <87zlp6pv24.fsf@basil.nowhere.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zlp6pv24.fsf@basil.nowhere.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1340 Lines: 31 On Fri, Jun 27, 2008 at 08:54:59PM +0200, Andi Kleen wrote: > Joerg Roedel writes: > > > On Fri, Jun 27, 2008 at 12:39:45PM -0400, Muli Ben-Yehuda wrote: > >> On Fri, Jun 27, 2008 at 04:47:29PM +0200, Andi Kleen wrote: > >> > >> > Also it should ideally describe that there is a trade off between > >> > reliability and performance with IOMMU enabled. > >> > >> I agree that there's a performance tradeoff with current generation > >> hardware and ingerfaces, but it wouldn't be fair to single out a > >> single IOMMU implementation ;=) > > > > True. At least for the case without device isolation I have some > > optimizations in mind which will minimize the performance tradeoff. I > > hope to have them ready for 2.6.28 :) > > Not sure that would be very useful. Outside of virtualization device > isolation is the main feature of an IOMMU on a native kernel. I agree that device isolation is one of the a main usage scenarios for an IOMMU. But if somebody want to use it for virtualization and doesn't need device isolation this optimization would be usefull. Joerg -- 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/