[ofa-general] Setting the rate in Infiniband.

[Ashwath Narasimhan]

Hello,
Problem:--
I am trying to set the "Rate" and "MTU" in infiniband using the config file
(opensm QoS) but I realize that I cannot set Rates like 500Mbps or 100Mbps.
The infiniband rates start from 2.5Gbps. (IBT specification vol 1 -> page
917, Table 207 "PathRecord" )

Background:--
The reason why I need such small rates is because I interface the Infiniband
HCA to an FPGA via an Infiniband physical link.  Imagine the FPGA as a
simple repeater that simply forwards the infiniband signals to the Target
HCA. The FPGA cannot handle such a high data rate and neither do I have as
much memory as required to buffer it on the FPGA (I might drop packets if
the buffer becomes full). Hence I wish to limit the rate to say 100Mbps
instead of 2.5Gbps.

Question:-
How can I set rates less than 2.5Gbps? Can this be changed at all?

regards,
Ashwath
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