Processors interconnect fabric with relay broadcasting and accumulation of partial responses

A processing unit for a data processing system including a plurality of processing units, said processing unit comprising:

• one or more processor cores;
• and
• interconnect logic, coupled to each communication link of that processing unit, that broadcasts requests received from one of multiple others of said plurality of processing units to one or more of said plurality of processing units;
• said interconnect logic including a partial response data structure including a plurality of entries each associating a partial response field with a plurality of flags respectively associated with each processing unit containing a snooper from which that processing unit will receive a partial response, wherein said interconnect logic accumulates partial responses of processing units by reference to said partial response field to obtain an accumulated partial response, and when said plurality of flags indicate that all processing units from which partial responses are expected have returned a partial response, outputs said accumulated partial response.

A method of data processing in a data processing system including a plurality of processing units, said method comprising:

• broadcasting requests received from one of multiple others of said plurality of processing units to one or more of said plurality of processing units;
• and
• in a partial response data structure including a plurality of entries each associating a partial response field with a plurality of flags respectively associated with each processing unit containing a snooper from which that processing unit will receive a partial response, accumulating partial responses of processing units by reference to said partial response field to obtain an accumulated partial response;
• setting one or more flags among said plurality of flags to indicate processing units from which partial responses have been received;
• and
• when said plurality of flags indicate that all processing units from which partial responses are expected have returned a partial response, outputting said accumulated partial response.