To provide for the processing of priority data elements between a host processor and a co- processor that exchange such data elements using a queue, the host processor determines a priority of a data element received from an application. If the priority is higher than a lowest possible priority value, at least one lower priority data element within the queue may be identified and modified thereby temporarily removing it from the queue. When the priority data element is written into the queue a query packet is included that will cause the co-processor to return information regarding a last executed queued data element. Based on the returned information, the host processor can determine one or more unmodified data elements (uniquely corresponding to the one or more modified queued data elements) to be written into the queue in accordance with a sequence of the previously modified queued data elements.