Date: Fri, 30 Nov 2001 02:22:01 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: John Vinters <johnv@jbg.co.uk> Cc: hackers@FreeBSD.ORG Subject: Re: FreeBSD performing worse than Linux? Message-ID: <200111301022.fAUAM1U09317@apollo.backplane.com> References: <bulk.69732.20011128081135@hub.freebsd.org> <3C052E84.3CF81084@jbg.co.uk>
next in thread | previous in thread | raw e-mail | index | archive | help
:I managed to track the problem down to the duplex settings on both the
:Ethernet cards (AT-2500 TX, Realtek 8139 based, AFAIK) and the 10/100
:Switch. Forcing both the cards and the switch to particular settings
:cured the problem, and lead to a massive performance increase.
:
:FTP seems to be particularly badly affected by the constant collisions
:(causing backoff). The problem can be tricky to find as the switch
:wasn't perceptably showing collisions on the collision LED, but viewing
:the switch stats showed a different story!
It probably wasn't collision backoff. It was probably packet loss
due to the switch and the host getting confused over the duplex
setting. i.e. where the switch thought it was one thing and the
host thought it was another.
The usual solution to this sort of switch/host confusion is to turn
off autonegotiation on both sides and hardwire the duplex to
full. On both sides. I've occassionally had similar problems
(not in the last year or two, though... but definitely with older
cards and switches).
-Matt
:I've noticed similar problems with Linux and certain cards (it was a
:while ago).
:
:John Vinters
:<johnv@jbg.co.uk>
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200111301022.fAUAM1U09317>