I/O COHERENT REQUEST NODE FOR DATA PROCESSING NETWORK WITH IMPROVED HANDLING OF WRITE OPERATIONS

A method and apparatus for data transfer in a data processing network uses both ordered and optimized write requests. A first write request is received at a first node of the data processing network is directed to a first address and has a first stream identifier. The first node determines if any previous write request with the same first stream identifier is pending. When a previous write request is pending, a request for an ordered write is sent to a Home Node of the data processing network associated with the first address. When no previous write request to the first stream identifier is pending, a request for an optimized write is sent to the Home Node. The Home Node and first node are configured to complete a sequence of ordered write requests before the associated data is made available to other elements of the data processing network.