[Beowulf] pci-e netwokr adapters

Mark Hahn hahn at physics.mcmaster.ca
Fri Mar 24 05:57:47 PST 2006

> Any one have success running gig-e through the pci-e bus?

why would you expect it to be different?
pci-e exists mainly to provide headroom (ie, 16x), as well as some 
improvements to configurability (vendors can balance lanes per slot).

for low-latency NICs, pci-e shaves off some time, but that's not 
relevant for ethernet.

> Would cpu load be reduced greatly by using these rather than the onboard broadcom gig-e?

I'd be pretty surprised - nics have been busmastering for quite a while.
do you find the CPU load is great with broadcom nics?

> so far I've only see 1x pci-e gig-e, anything higher say 4x pci-e at a reasonable price?

1x pci-e is full-duplex 250 MB/s, no?  so what would be the point?
or do you mean a multi-port nic?

> viable option to older myrinet gear?

hardly.  plain old myri 2G is still ~3 us...

regards, mark hahn.

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