SQ Drain (SQD) State
Under Software Control, SQD Is Entered From...
...the RTS state. Software transitions a QP from the SQD state to the RTS state using the Modify QP verb call.
Used When Altering Operational QP's Characteristics
Software may need to alter the operational characteristics of a QP that is already fully operational (i.e., it is in the RTS state). It would be dangerous to do so while the QP still has one or more messages in flight to the remote QP. Commanding an operational QP to enter the SQD state effectively causes the QP:
- To complete the transmission of all in-progress messages,
- wait until all expected responses have been received,
- retire all in-progress WQEs,
- create their respective CQEs,
- and then pause.
No new message transmissions ...