FreeBSD 5.4 network performance with SMP
Robert Lindgren
robert at orcafat.com
Sun Oct 2 13:09:46 PDT 2005
Hi All,
I have a strange little problem on Dell 1800's. If HT,SMP is enabled in the
kernel (5.4p7), performance on the integrated em0 is not especially good,
half the speed of the current 100Mbit connection. This is true from the
server and a little better to the server. On a pci rl0 card in the same
machine performance is even worse. About 15Mbit from the server!
Then I read a lot of people having poor performance from the rl0 cards and a
lot of FreeBSD people bashing it for being crap, even in the source code for
the module it's stated that these cards aren't so good. I guess that is right
to some extent but not 15Mbit/sec.
So when I rebuilt the kernel without HT and SMP I get full wirespeed from the
em0 and the rl0 (100Mbit/sec). Is there anything I've been doing wrong to get
hit by this poor performance with the SMP kernel. I read the disabling USB
could improve performance but tried that with the HT kernel without any luck.
The server has 1 3Ghz cpu, and I would prefer too run a HT enabled kernel, but
not with that kind of performance, so please advice. The same machines (Dell
1800) run linux with HT enabled without any network performance degradation.
Best regards
Robert Lindgren
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