Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758752AbXFZPhM (ORCPT ); Tue, 26 Jun 2007 11:37:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757111AbXFZPhA (ORCPT ); Tue, 26 Jun 2007 11:37:00 -0400 Received: from one.firstfloor.org ([213.235.205.2]:54291 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756113AbXFZPhA (ORCPT ); Tue, 26 Jun 2007 11:37:00 -0400 Date: Tue, 26 Jun 2007 17:36:58 +0200 From: Andi Kleen To: Muli Ben-Yehuda Cc: Andi Kleen , Andrew Morton , "Keshavamurthy, Anil S" , linux-kernel@vger.kernel.org, gregkh@suse.de, suresh.b.siddha@intel.com, arjan@linux.intel.com, ashok.raj@intel.com, davem@davemloft.net, clameter@sgi.com Subject: Re: [Intel IOMMU 00/10] Intel IOMMU support, take #2 Message-ID: <20070626153658.GB5244@one.firstfloor.org> References: <20070619213701.219910000@askeshav-devel.jf.intel.com> <20070625234550.058635cb.akpm@linux-foundation.org> <200706260912.45838.ak@suse.de> <20070626111324.GB4320@rhun.ibm.com> <20070626150940.GC8274@rhun.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070626150940.GC8274@rhun.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1311 Lines: 35 On Tue, Jun 26, 2007 at 11:09:40AM -0400, Muli Ben-Yehuda wrote: > On Tue, Jun 26, 2007 at 05:56:49PM +0200, Andi Kleen wrote: > > > > > - The IOMMU can merge sg lists into a single virtual block. This could > > > > potentially speed up SG IO when the device is slow walking SG > > > > lists. [I long ago benchmarked 5% on some block benchmark with > > > > an old MPT Fusion; but it probably depends a lot on the HBA] > > > > > > But most devices are SG-capable. > > > > Your point being? > > That the fact that an IOMMU can do SG for non-SG-capble cards is not > interesting from a "reason for inclusion" POV. You misunderstood me; my point was that some SG capable devices can go faster if they get shorter SG lists. But yes for non SG capable devices it is also interesting. I expect it will obsolete most users of that ugly external patch to allocate large memory areas for IOs. That's a point I didn't mention earlier. > > Also the user interface for X server case needs more work. > > Is anyone working on it? It's somewhere on the todo list. -Andi - 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/