[ofa-general] performance to call ibv_poll_cq() vs. call select() on completion channel

[Roland Dreier]

 > 	I understand that ops.poll_cq is actually ibv_cmd_poll_cq(), right ?

No, not for most devices.  Look at libmthca, etc to see what the poll_cq
method is set to.

 > 	Do you mean during ibv_poll_cq() call, there is no system call involved ?

Right, for most devices poll_cq can be done just by looking at memory in
userspace without involving the kernel at all.