[Beowulf] Re: typical latencies for gigabit ethernet
d.love at liverpool.ac.uk
Mon Jun 29 15:43:53 PDT 2009
Rahul Nabar <rpnabar at gmail.com> writes:
> I thought so! :) Lazy person's first shot. Now I will try ethtool.
It's not relevant with all NICs. Some use driver module parameters.
> Any way to verify if I do?
Consult the NIC's documentation.
> Ah! So my "real" latencies are 140/2 = 70 microsecs.
I see ping times of ~70μs between the nVidias I posted data on, and they
have an MPI latency of ~12μs. If you want a measurement/benchmark for
MPI performance use IMB, like for the results I posted. Otherwise
people sometimes use netpipe. If you want basic Ethernet (Layer 2)
figures, look for Hughes-Jones' ethmon, somewhere under
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