From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gagan Arneja Subject: Re: [RFC] New driver API to speed up small packets xmits Date: Thu, 10 May 2007 13:25:19 -0700 Message-ID: <46437FAF.50004@vmware.com> References: <46435412.50800@hp.com> <1178820423.17393.3.camel@w-sridhar2.beaverton.ibm.com> <464375F9.1050600@gmail.com> <1178827887.4062.90.camel@localhost> <46437D53.7000209@gmail.com> <1178828480.4062.98.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Gagan Arneja , Sridhar Samudrala , Rick Jones , Krishna Kumar2 , Evgeniy Polyakov , netdev@vger.kernel.org To: hadi@cyberus.ca Return-path: Received: from smtp-outbound-1.vmware.com ([65.113.40.141]:35623 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755383AbXEJUZU (ORCPT ); Thu, 10 May 2007 16:25:20 -0400 In-Reply-To: <1178828480.4062.98.camel@localhost> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > For example: > my biggest challenge with the e1000 was just hacking up the DMA setup > path - i seem to get better numbers if i dont kick the DMA until i stash > all the packets on the ring first etc. It seemed counter-intuitive. That seems to make sense. The rings are(?) in system memory and you can write to them faster. Kicking the DMA needs a transaction on the PCI bus, which can be painfully slow... -- Gagan