[ofa-general] IB credit-based flow control

[Andy Grover]

Hi,

Steve and I have been working to debug RDS's credit-based flow control, 
and I happened to notice that IB already implements this (see ib spec 
section 9.7.7.2).

So, why is it necessary for a ULP like RDS to implement its own flow 
control? It looks like IB's flow control should result in no RNR 
retries, yet without protocol-level FC, we see RNR retries.

Thanks -- Regards -- Andy