[openib-general] [PATCH] uverbs rdma example (updated)

[Roland Dreier]

    Michael> Hmm. rx_depth is unused. tx_depth is used.

Where?  If I search through the whole patch for "tx_depth," the only
place I see it do anything at all is in

+	ctx->cq = ibv_create_cq(ctx->context, rx_depth + tx_depth, NULL);

but I don't see how more than one send can be outstanding.

    Michael> Hmm. Thats what I do for receieve - polling on data.

    Michael> You cant assume the hardware will not read the buffer
    Michael> until you get a send completion, so you wont be able to
    Michael> re-use the send buffer. Since polling cq is done after
    Michael> post, it does not affect the latency in any way.

That makes sense.  Also I forgot that without a completion we can
never clean up the WQE buffer.

 - R.