From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Gilligan Subject: Re: the maximal speed of pktgen with 1Gbps NIC Date: Wed, 22 Jul 2009 10:12:17 -0700 Message-ID: <4A674871.4090901@vyatta.com> References: <60230E21F17E384C9BF0B9C98D9E3FDC04BDC92E@sgp-sg-mb02.sgp.agilent.com> <1248275552.4058.0.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jesper Dangaard Brouer , jon_zhou@agilent.com, netdev@vger.kernel.org To: Ben Hutchings Return-path: Received: from mail.vyatta.com ([76.74.103.46]:52690 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753963AbZGVRMI (ORCPT ); Wed, 22 Jul 2009 13:12:08 -0400 In-Reply-To: <1248275552.4058.0.camel@localhost> Sender: netdev-owner@vger.kernel.org List-ID: Ben Hutchings wrote: > On Wed, 2009-07-22 at 14:56 +0200, Jesper Dangaard Brouer wrote: >> On Wed, 22 Jul 2009, jon_zhou@agilent.com wrote: >> >>> anyone knows the maximal speed of pktgen with 1Gbps NIC? >> You are limited by the number of packets per second (pps) your machine can >> generate. This limitation is given by the CPU speed and the NIC used. >> >> The maximum pps I have seen with pktgen at 1Gbit/s is 1200 kpps. >> >> 1Gbit/s wire speed pps with 64 bytes packets is approx 1953 kpps. >> (1000*10^6/(64*8) = 1953125) > [...] > > You need to take the inter-packet gap into consideration too. Yes. Usually when people talk about the "64-byte PPS rate" they are referring to the maximum rate of minimum size ethernet frames. The 64-bytes includes the src/dst addr fields, type field and CRC, but does not include the preamble (7 bytes), SOF (1 byte) or IPG (12 bytes). Adding these in gives a minimum size frame of 84 bytes. This works out to a max rate of ( 1,000,000,000 / (84 * 8) ) = 1,488,095 PPS. Bob.