OUT-OF-ORDER PROBING IN AN IN-ORDER SYSTEM

A command filter selectively forwards received commands to a command queue for in-order execution. If the received command is a probe response command or if probe response information is extracted.from other commands, the probe response is stored in a storage location other than the command queue and executed out-of-order. Data movements specified by memory modifying commands already in the command queue and affecting the cache line in question are also performed out-of-order and the memory modifying command is discarded when it is removed in-order from the command queue.