[SunHELP] Extremely poor network performance after OBP upgrade(and os reinstal)

Chris Anderson christop at charm.net
Tue Aug 23 01:59:56 CDT 2005

It may not be the Sun at all.  If the other end is a Linux machine,
there is a bug in the e1000 driver in the 2.6 kernel distributed with
RHEL4.1 which causes nice Intel 1000 mbit cards to perform worse than 10
mbit cards in certain cases with tcp.  Work around is here:


The difference is rather dramatic:

# ethtool -K eth1 tso on
# iperf -c
[  3]  0.0-21.4 sec  4.77 MBytes  1.87 Mbits/sec

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