[Openib-windows] Net perf with small msg size

[Yossi Leybovich]

Hi Fab,

I looked into the net perf issue - machine stuck when using many small
massages.
I compared the network dump between Ethernet and IPoIB (on the same test
case) and it looks like that the nagel algorithm is not working well
with IPoIB.
While testing with socket size of 512 bytes and massage size of 1 byte I
notice the following difference.
While in Ethernet the TCP stack accumulate msg (send packets of 512
bytes ) in the IPoIB I notice we send many packets of 3-4 bytes.

Do you have any idea for this behavior?

(NOTE: that the delay ack algorithm was enable as well)

Attached is ethereal file that was capture on the server side (rcv side)
Msg size = 1
Socket Buffer = 512

Thanks
Yossi 
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