Date: Thu, 13 Dec 2001 10:52:23 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Thomas Zenker <thz@Lennartz-electronic.de> Cc: stable@FreeBSD.ORG Subject: Re: TCP stack still hosed? Message-ID: <200112131852.fBDIqNF70268@apollo.backplane.com> References: <20011213105451.A738@mezcal.tue.le> <200112131102.fBDB2WQ66827@apollo.backplane.com> <20011213185153.A365@mezcal.tue.le>
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Very interesting! Well, I'm glad you tracked it down. Hopefully the
USB authors can solve the buffering issues. We don't want to change
the default back to its old lower value because it completely kills
performance over the more common ethernete interfaces.
You can also try dropping your USB ethernet down from 100BaseT to 10BaseT
(if it happens to be running at 100). Placing a 100BaseT ethernet
on a USB connection has always seemed to be an oxymoron to me. I don't
know why anyone even sells such a product.
-Matt
Matthew Dillon
<dillon@backplane.com>
:On Thu, Dec 13, 2001 at 03:02:32AM -0800, Matthew Dillon wrote:
:> If you do, we need tcpdumps of the test connection. Also, I recommend
:> testing between two hosts with normal ethernet cards in them
:> (i.e. not USB) as a double-check.
:>
:> -Matt
:> Matthew Dillon
:> <dillon@backplane.com>
:
:the most impacting change is in tcp_usrreq.c
:----------------------------
:revision 1.51.2.10
:date: 2001/11/30 19:54:05; author: alfred; state: Exp; lines: +3 -3
:MFC: 1.64 (larger default tcp send/recieve buffers)
:----------------------------
:
:It seems that the switch and/or the USB/ethernet adaptor is overrun
:by the larger sendspace. So setting sysctl net.inet.tcp.xxxspace=16384
:on the USB/ethernet system solves the problem mostly.
:
:Thomas
:
:
:-- Thomas Zenker
: c/o Lennartz electronic GmbH
: Bismarckstrasse 136, D-72072 Tuebingen, Germany
: Phone: +49-(0)7071-93550
: Email: thz@lennartz-electronic.de
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