Date: Thu, 12 Jul 2001 01:04:08 +0200 From: Thierry Herbelot <thierry@herbelot.com> To: Martin Karsten <Martin.Karsten@KOM.tu-darmstadt.de> Cc: freebsd-net@FreeBSD.ORG, oscar@ac.upc.es Subject: Re: UDP packet loss on FreeBSD 4.x Message-ID: <3B4CDB68.8D06CA81@herbelot.com> References: <200107111512.RAA30280@KOM.tu-darmstadt.de>
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Hello, FWIW, I've recently built a test bench where I used P-III-450 PCs running 4-port dc(4) NIC (DLINK DFE-570-TX). The tests I've done have shown it's posible with the 4.2-R stock sources (and a tailored kernel) to send AND simultaneously send more than 20k packets/sec with a Packet Loss Rate of less than 1e-5 (when the ports are configured for 100Mbps - full duplex ; the max "correct" throughput for 10Mbps-FD is more like 8 to 10Kpacket/s, still sending and receiving simultaneously) the tests have been done with smallish packets (64 bytes/packet) and 1, 2, 3, 4, and 12 ports per machine (in each case, a total of 20 Kpack/s could be processed that is around 1800packet/s for 12 simultaneous live ports) the packets sent were UDP or raw IP streams (I did not use the xl(4) driver) TfH Martin Karsten wrote: > > Greetings, > > I have observed the following behaviour on FreeBSD 4.x platforms (4.0 till > 4.3 seem to be affected). > > When receiving a sufficiently fast stream of UDP packets (the borderline > seems to be around 3,500 packets/sec for e.g. the 'xl' driver on a 450MHz > Pentium), an application on the receiving host does not receive all packets > anymore, depending on which nic driver is used. A fraction of the lost > packets is reported in net.inet.ip.intr_queue_drops, but not all. > > Tests have shown that the losses occur for the 'xl' or 'ti' drivers, whereas > the 'fxp' and 'de' driver don't seem to be affected. > > On FreeBSD 3.4, no such losses happened and one could easily transmit more > than 10,000 packets/sec between adjacent machines. > > Is this a knowm problem and is there a chance that it is fixed? Is there > potentially a quick solution for it? > > Further, might this problem be related to an earlier report (08 Jan 2001) > sent with the subject "On the performance of the xl driver" by Oscar-Ivan > Lepe-Aldama? > > Thanks in advance, > Martin > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-net" in the body of the message -- Thierry Herbelot To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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