Date: Tue, 13 Feb 2001 16:53:13 -0800 (PST) From: Luigi Rizzo <rizzo@aciri.org> To: net@freebsd.org Subject: fxp performance ? Message-ID: <200102140053.f1E0rET55388@iguana.aciri.org>
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Hi, don't know how many of you have ever tried this... I am trying to generate (send only) packets at maximum rate on a 100Mbit ethernet, which means using 64-byte packets and, once you do the math (counting preamble, packet and inter-packet gap), results in some 148.000 packets-per-second (and just to get the idea, this also means that a new packet is transmitted every 6.72us). Note, the above is not trivial as you need a fast CPU, and probably some tricks in order to avoid parf of the overhead of ip_output(). In any case, on botu a P3-650 and an Athlon-750, I managed to achieve this speed using the "dc" driver. When i tried the same with the 'fxp' driver, there was no way i managed to go above 105-110.000 packets per second (meaning an average of 9.1us/packet). Any idea on what is going on ? I have spent quite some time in the fxp driver and cannot really tell where the problem is. Unfortunately my diagnostic tools do not let me see what is going on on the wire, whether the spacing is larger than it should be, etc. etc. cheers luigi ----------------------------------+----------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . ACIRI/ICSI (on leave from Univ. di Pisa) http://www.iet.unipi.it/~luigi/ . 1947 Center St, Berkeley CA 94704 Phone: (510) 666 2927 ----------------------------------+----------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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