Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265586AbTFMXxc (ORCPT ); Fri, 13 Jun 2003 19:53:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265588AbTFMXxc (ORCPT ); Fri, 13 Jun 2003 19:53:32 -0400 Received: from dp.samba.org ([66.70.73.150]:48602 "EHLO lists.samba.org") by vger.kernel.org with ESMTP id S265586AbTFMXxb (ORCPT ); Fri, 13 Jun 2003 19:53:31 -0400 Date: Sat, 14 Jun 2003 10:03:42 +1000 From: Anton Blanchard To: "Feldman, Scott" Cc: "David S. Miller" , haveblue@us.ibm.com, hdierks@us.ibm.com, dwg@au1.ibm.com, linux-kernel@vger.kernel.org, milliner@us.ibm.com, ricardoz@us.ibm.com, twichell@us.ibm.com, netdev@oss.sgi.com Subject: Re: e1000 performance hack for ppc64 (Power4) Message-ID: <20030614000342.GE32097@krispykreme> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1514 Lines: 35 > I thought the answer was no, so I double checked with a couple of > hardware guys, and the answer is still no. Hi Scott, Thats a pity, the e100 docs on sourceforge show it can do what we want, it would be nice if e1000 had this feature too :) 4.2.2 Read Align The Read Align feature is aimed to enhance performance in cache line oriented systems. Starting a PCI transaction in these systems on a non-cache line aligned address may result in low performance. To solve this performance problem, the controller can be configured to terminate Transmit DMA cycles on a cache line boundary, and start the next transaction on a cache line aligned address. This feature is enabled when the Read Align Enable bit is set in device Configure command (Section 6.4.2.3, "Configure (010b)"). If this bit is set, the device operates as follows: * When the device is close to running out of resources on the Transmit * DMA (in other words, the Transmit FIFO is almost full), it attempts to * terminate the read transaction on the nearest cache line boundary when * possible. * When the arbitration counters feature is enabled (maximum Transmit DMA * byte count value is set in configuration space), the device switches * to other pending DMAs on cache line boundary only. - 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/