Re: Problem with duplex Gigabit TCP on SPARC T1/tg3

From: Elad Lahav
Date: Fri Sep 26 2008 - 22:08:12 EST


Hi David,

We meet again - I guess you're the only person answering questions in the Linux community ;-)

The first interface, eth0, will show all kinds of performance issues.
The other ones, eth1, eth2, and eth3, should be mostly fine.
Actually, in this case I'm using eth0 as an admin interface, and eth1-eth3 for the experiments.

There are some other anomalies, though. eth2 and eth3 (BCM5704) exhibit slightly worse performance than eth1, though this may be attributed to the different card or the bus (I think eth0 and eth1 are on-board).
Also, the interrupt rate varies considerably over time, from around 4000/sec to over 15000/sec, with no apparent reason. If I understand the driver code correctly, the interface should be constantly polling, so the interrupt rate should be fairly steady (and low).
None of this explains the duplex issues, though. Unfortunately, there are too many variables involved, compared with the other machines I'm experimenting with (processor type and speed, NIC make and model, etc.).

--Elad

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