From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754714Ab0ALTCI (ORCPT ); Tue, 12 Jan 2010 14:02:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754645Ab0ALTCG (ORCPT ); Tue, 12 Jan 2010 14:02:06 -0500 Received: from server109h.appriver.com ([72.32.253.92]:4285 "EHLO server109.appriver.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754597Ab0ALTCF convert rfc822-to-8bit (ORCPT ); Tue, 12 Jan 2010 14:02:05 -0500 X-Policy: GLOBAL - intcomgrp.com X-Policy: GLOBAL - intcomgrp.com X-Primary: jkosin@intcomgrp.com X-Note: This Email was scanned by AppRiver SecureTide X-ALLOW: JKosin@intcomgrp.com ALLOWED X-Virus-Scan: V- X-Note: Spam Tests Failed: X-Country-Path: UNITED STATES->UNITED STATES X-Note-Sending-IP: 216.54.13.100 X-Note-Reverse-DNS: mail.intcomgrp.com X-Note-WHTLIST: JKosin@intcomgrp.com X-Note: User Rule Hits: X-Note: Global Rule Hits: G113 G114 G115 G116 G120 G121 G132 G219 X-Note: Encrypt Rule Hits: X-Note: Mail Class: ALLOWEDSENDER X-Note: Headers Injected X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Subject: RE: arm: Optimization for ethernet MAC handling at91_ether.c Date: Tue, 12 Jan 2010 14:03:46 -0500 Message-ID: <3DBBD805E3BA064A87F551C0E8BD36740289741C@MAILSRV.intcomgrp.com> In-Reply-To: <3DBBD805E3BA064A87F551C0E8BD367402897418@MAILSRV.intcomgrp.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: arm: Optimization for ethernet MAC handling at91_ether.c Thread-Index: AcqTspWCmnn7FjRuR3SQzPFeTMxe6wAANsBQAAGbhMA= References: <3DBBD805E3BA064A87F551C0E8BD3674028973F5@MAILSRV.intcomgrp.com> <4B4CA4E5.7030800@gmail.com> <3DBBD805E3BA064A87F551C0E8BD36740289740E@MAILSRV.intcomgrp.com> <4B4CBA93.4090909@gmail.com> <3DBBD805E3BA064A87F551C0E8BD367402897418@MAILSRV.intcomgrp.com> From: "James Kosin" To: "James Kosin" , "Eric Dumazet" Cc: , "Linux Netdev List" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/12/2010 1:50 PM, James Kosin wrote: > -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Eric Dumazet > Sent: Tuesday, January 12, 2010 1:08 PM > To: James Kosin > Cc: linux-kernel@vger.kernel.org; Linux Netdev List > Subject: Re: arm: Optimization for ethernet MAC handling at91_ether.c > > Le 12/01/2010 18:51, James Kosin a écrit : >> On 1/12/2010 11:40 AM, Eric Dumazet wrote: > > > I know. Actually, I am using the hardware; and the part is capable of more than this driver is displaying. > > 1) The part is able to queue up two packets (1) actively being transmitted, and (1) queued up behind that packet. The driver doesn't exploit this; probably because this would cause some confusion, since we wouldn't really know which packet failed when this happens. > > 2) TX performance is so..so. With bing on another computer using '-z' option it is reporting a fairly good value of 74Mbps. I'll have to try with a re-compiled kernel at some point to give better feedback if we can improve this more. > > Your interpretation makes some sense on the transmit side. The RX currently has a DMA queue that extends to a depth of 9 (currently). So getting one transmit out before checking the RX may improve things a bit. > Scratch that. The interrupt doesn't queue up or send another packet directly. So, it wouldn't help on performance here. But, may in other implementations that queue/transmit packets in the ISR. At least in the case where the transmitter is limited to one. James