> I have the envious task of figuring out whether SRQ is being used in > an SRP application (which I have very little knowledge about). I > only have IB transport layer traces from the customer. From the > traces I can see Valid Credits in the Syndrome field of the AETH in > RDMA_ReadResponse_First/last messages. Although there are a bunch > of RC SENDs where the AETH syndrome field is Invalid, unfortunately > I cannot seem to correlate these RC SENDS with the RDMA > read/responses. My questions is, since the RDMA response AETH field > has valid CC credits is it saying SRQ is not being used?
As I guess you know, if end-to-end credits are used on an RC connection, then SRQ cannot be used on that connection. The opposite implication does not hold: eg a TCA might not implement the optional end-to-end flow control protocol, and hence a non-SRQ connection might still not use end-to-end flow control. Also end-to-end flow control is negotiated for each direction of a connection independently, so you might see valid end-to-end credits sent in only one direction. Essentially the only thing you can learn from a wire-level trace is the following: if you see an AETH with valid end-to-end credits being sent from CA X, then the corresponding receive queue on CA X is not attached to an SRQ. I don't believe there is anything further you can deduce. (Certainly invalid end-to-end credits do not imply that an SRQ is being used, they simply imply that the end-to-end flow control protocol is not in use) - R. -- Roland Dreier <rola...@cisco.com> || For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/index.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
