From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chris Friesen" Subject: Re: questions on NAPI processing latency and dropped network packets Date: Mon, 21 Jan 2008 17:15:15 -0600 Message-ID: <47952783.8080505@nortel.com> References: <478654C3.60806@nortel.com> <4794F848.9020402@nortel.com> <47950A71.5010304@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Ben Greear Return-path: Received: from zrtps0kp.nortel.com ([47.140.192.56]:62465 "EHLO zrtps0kp.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756041AbYAUXP0 (ORCPT ); Mon, 21 Jan 2008 18:15:26 -0500 In-Reply-To: <47950A71.5010304@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: Ben Greear wrote: > Chris Friesen wrote: > >> Is there anything else we can do to minimize the latency of network >> packet processing and avoid having to crank the rx ring size up so high? > > > Why is it such a big deal to crank up the rx queue length? Seems like > a perfectly normal way to handle bursts like this... It means that the latency for handling those packets is higher than it could be. Draining 4096 packets from the queue will take a while. Ideally we'd like to bring the latency down as much as possible, and then bump up the rx queue length to handle the rest. Chris