AXI-5 User Loopback Signaling use cases?

The main use case is described in the Specification

User Loopback signaling permits an agent that is issuing requests to store information that is related to the transaction in an indexed table.

The transaction response can then use a fast table index to obtain the required information, rather than requiring a more complex lookup that uses the transaction ID.

To expand on this, normally a manager interface would use the AxID to match a transaction response to the original request.  However, this can be complicated by transactions using the same AxID (for ordering reasons), and there needs to be some process to match the returned AxID to the correct transaction tracking entry in the manager.

Using the Loopback signals would allow a manager to assign AxLOOP to value that is easily mapped to the right transaction tracking entry, and is independent of the AxID used.

The main use case is described in the Specification

User Loopback signaling permits an agent that is issuing requests to store information that is related to the transaction in an indexed table.

The transaction response can then use a fast table index to obtain the required information, rather than requiring a more complex lookup that uses the transaction ID.

To expand on this, normally a manager interface would use the AxID to match a transaction response to the original request.  However, this can be complicated by transactions using the same AxID (for ordering reasons), and there needs to be some process to match the returned AxID to the correct transaction tracking entry in the manager.

Using the Loopback signals would allow a manager to assign AxLOOP to value that is easily mapped to the right transaction tracking entry, and is independent of the AxID used.

Thanks Christopher Tory  for your clarification.