From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263459AbTJOPp5 (ORCPT ); Wed, 15 Oct 2003 11:45:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263460AbTJOPp5 (ORCPT ); Wed, 15 Oct 2003 11:45:57 -0400 Received: from zcars0m9.nortelnetworks.com ([47.129.242.157]:37026 "EHLO zcars0m9.nortelnetworks.com") by vger.kernel.org with ESMTP id S263459AbTJOPp4 (ORCPT ); Wed, 15 Oct 2003 11:45:56 -0400 Message-ID: <3F8D6BB0.7060809@nortelnetworks.com> Date: Wed, 15 Oct 2003 11:45:52 -0400 X-Sybari-Space: 00000000 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: Linux Kernel Subject: incoming packet latency in 2.4.[18-20] 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 There is an issue with incoming packet latency in the kernels mentioned. It seems that if you send in a burst of messages, the amount of time it takes to wake the listening process is dependent on the size of the message burst. 2.4.18-2.4.20 all show this behaviour, 2.6 doesn't. Some numbers for a udp message size of 2 bytes: 1 packet, average latency 12 usecs 10 packets, average latency 66 usecs 100 packets, average latency 477 usecs Is this a known issue? Is there an easy way to fix this, or is it something inherent in the 2.4 architecture? Thanks, Chris -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com