Image Number 10 for United States Patent #6263409.
A data processing system and method for substituting selected requests with substitute requests that perform the same or similar end function but achieve increased system performance are disclosed. Those requests that have a selected request characteristic are identified and converted or replaced with a predetermined substitute request. The substitute requests perform at least part of the function of the identified requests. The data processing system may include two or more processors, and the selected request characteristic may be that a write data packet of an identified write request was not changed by a first processor. A substitute request may update directory information associated with the identified write request but may not write to associated data packet to memory. The directory information can indicate whether identified memory locations are currently owned by a processor. The substitute request may also send the associated write data packet from the first processor to a second processor via a processor-to-processor interface. It may be determined whether a processor block has changed selected data by examining a function code of a write type request.