Date: Sun, 30 Dec 2001 23:04:32 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Mike Silbersack <silby@silby.com> Cc: Josef Karthauser <joe@tao.org.uk>, Tomas Svensson <tsn@gbdev.net>, <freebsd-hackers@FreeBSD.ORG> Subject: Re: FreeBSD performing worse than Linux? Message-ID: <200112310704.fBV74Wb18947@apollo.backplane.com> References: <Pine.BSF.4.30.0112291355370.1093-100000@niwun.pair.com>
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:I'm going to blame the USB ethernet driver for dropping packets; Thomas
:Zenker has been reporting similar problems on -net. He says that he did
:not have problems with packet loss with 4.3, but has not been able to
:track down what changed. Maybe you could compare notes with him and see
:what you can come up with.
:
:Mike "Silby" Silbersack
new-reno was artifically limiting the max number of in-transit
packets to 4. This is probably why the USB ethernet worked
with 4.3, but it destroyed TCP performance for everything else
and was removed.
I don't think there is kernel solution to the USB problems, short
of fixing the driver (if that's even possible). The packets are
being sent from the server and the only thing the client has
control over is the receive window advertisement. You could artifically
reduce the window advertisement on the client to deal with lots of small
packets but it would destroy performance for larger packets / data
streams.
-Matt
Matthew Dillon
<dillon@backplane.com>
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