According to a method of data processing, a memory controller receives a plurality of data prefetch requests from multiple processor cores in the data processing system, where the plurality of prefetch load requests include a data prefetch request issued by a particular processor core among the multiple processor cores. In response to receipt of the data prefetch request, the memory controller provides a coherency response indicating an excess number of data prefetch requests. In response to the coherency response, the particular processor core reduces a rate of issuance of data prefetch requests.