We have just installed a small gigabit ethernet cluster using Linux
2.4.21 and an e1000 gigabit ethernet driver. Performance was woeful
using the default configuration with 250 usec. small message latencies
and only 200-300 Mbit/sec throughput for large messages. Some
experimentation with the driver parameters improved things somewhat to
50usec. and 900 Mbit/sec. However, things do not look quite right and
the controller hangs for larger message sizes without interrupt
throttling.
Can someone point us towards information on tuning gigabit ethernet on
linux for numerical cluster purposes? That is, where low latencies are
important and maximum throughput less so?
In particular, is it possible to set minimum latencies for small
messages (blocking mpi calls) and coalescing for message sizes
exceeding the packet size?
Pointers for parameters to prod and tune in the 2.4 kernel also
gratefully received.
Apologies if the subject is slightly off topic.
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