An array of a plurality of processing elements (PEs) are in a data packet-switched network interconnecting the PEs and memory to enable any of the PEs to access the memory. The network connects the PEs and their local memories to a common controller. The common controller may include a shared load/store (SLS) unit and an array control unit. A shared read may be addressed to an external device via the common controller. The SLS unit can continue activity as if a normal shared read operation has taken place, except that the transactions that have been sent externally may take more cycles to complete than the local shared reads. Hence, a number of transaction-enabled flags may not have been deactivated even though there is no more bus activity. The SLS unit can use this state to indicate to the array control unit that a thread switch may now take place.