Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261914AbUC0XEs (ORCPT ); Sat, 27 Mar 2004 18:04:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261919AbUC0XEr (ORCPT ); Sat, 27 Mar 2004 18:04:47 -0500 Received: from 1-2-2-1a.has.sth.bostream.se ([82.182.130.86]:42929 "EHLO K-7.stesmi.com") by vger.kernel.org with ESMTP id S261907AbUC0XEn (ORCPT ); Sat, 27 Mar 2004 18:04:43 -0500 Message-ID: <40660877.3090302@stesmi.com> Date: Sun, 28 Mar 2004 00:04:23 +0100 From: Stefan Smietanowski User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7b) Gecko/20040316 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jeff Garzik CC: linux-ide@vger.kernel.org, Linux Kernel , Andrew Morton Subject: Re: [PATCH] speed up SATA References: <4066021A.20308@pobox.com> In-Reply-To: <4066021A.20308@pobox.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1513 Lines: 36 Hi Jeff. > The "lba48" feature in ATA allows for addressing of sectors > 137GB, and > also allows for transfers of up to 64K sector, instead of the > traditional 256 sectors in older ATA. > > libata simply limited all transfers to a 200 sectors (just under the 256 > sector limit). This was mainly being careful, and making sure I had a > solution that worked everywhere. I also wanted to see how the iommu S/G > stuff would shake out. > > Things seem to be looking pretty good, so it's now time to turn on > lba48-sized transfers. Most SATA disks will be lba48 anyway, even the > ones smaller than 137GB, for this and other reasons. > > With this simple patch, the max request size goes from 128K to 32MB... > so you can imagine this will definitely help performance. Throughput > goes up. Interrupts go down. Fun for the whole family. What will happen when a PATA disk lies behind a Marvel(ous) bridge, as in most SATA disks today? Is large transfers mandatory in the LBA48 spec and is LBA48 really mandatory in SATA? And yes, I saw that the dmesg showed a Maxtor drive, but I'm uncertain if that disk of yours has a Marvel chip on or not, since newer Maxtors might (have) come out (already) without a Marvel chip, I just don't know. // Stefan - 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/