Data processing system, method and interconnect fabric for improved communication in a data processing system

Abstract

A data processing system includes a plurality of processing units each having a respective point-to-point communication link with each of multiple others of the plurality of processing units but fewer than all of the plurality of processing units. Each of the plurality of processing units includes interconnect logic, coupled to each point-to-point communication link of that processing unit, that broadcasts operations received from one of the multiple others of the plurality of processing units to one or more of the plurality of processing units.

1 . A data processing system, comprising: 
 a plurality of processing units each having a respective point-to-point communication link with each of multiple others of said plurality of processing units but fewer than all of said plurality of processing units;    wherein each of said plurality of processing units includes interconnect logic, coupled to each point-to-point communication link of that processing unit, that broadcasts operations received from one of said multiple others of said plurality of processing units to one or more of said plurality of processing units.    
   
   
       2 . The data processing system of  claim 1 , wherein: 
 said plurality of processing units are disposed within a plurality of processing nodes each including multiple processing units;    within each processing node, each processing unit is coupled to each other processing unit within that processing node by a respective point-to-point communication link; and    at least one processing unit in each processing node is coupled by a point-to-point communication link to a processing unit in a different processing node.    
   
   
       3 . The data processing system of  claim 2 , wherein no more than one processing unit in each processing node is coupled by a point-to-point communication link to a processing unit in a given other processing node.  
   
   
       4 . The data processing system of  claim 3 , wherein: 
 each point-to-point communication link coupling processing units within said plurality of processing nodes comprises a first tier link;    each point-to-point communication link coupling processing units in different processing nodes comprises a second tier link;    processing units coupled by said first tier links all follow a first uniform connectivity rule; and    processing units coupled by said second tier links all follow a second uniform connectivity rule.    
   
   
       5 . The data processing system of  claim 1 , wherein each point-to-point communication link comprises a uni-directional communication link.  
   
   
       6 . The data processing system of  claim 5 , wherein each said point-to-point communication link comprises one of a pair of point-to-point communication links having opposing directions of information flow.  
   
   
       7 . The data processing system of  claim 1 , wherein each of said plurality of processing nodes comprises a multi-chip module (MCM).  
   
   
       8 . A processing unit for a multi-processor data processing system, said processing unit comprising: 
 at least one master capable of initiating an operation;    at least one snooper capable of receiving an operation; and    interconnect logic having connections for a plurality of first tier point-to-point communication links to at least first and second processing units and for a second tier point-to-point communication link to a third processing unit, wherein said interconnect logic broadcasts operations received from one of said first and second processing units to said third processing unit and broadcasts operations received from third processing unit to said first and second processing unit.    
   
   
       9 . The processing unit of  claim 8 , wherein each point-to-point communication link comprises a uni-directional communication link.  
   
   
       10 . The processing unit of  claim 9 , wherein each said point-to-point communication link comprises one of a pair of point-to-point communication links having opposing directions of information flow.  
   
   
       11 . A multi-chip module, comprising: 
 a plurality of processing units in accordance with  claim 8;  and    a package containing said plurality of processing units.    
   
   
       12 . A method of communication in a data processing system, said method comprising: 
 providing a plurality of processing units each having a respective point-to-point communication link with each of multiple others of said plurality of processing units but fewer than all of said plurality of processing units; and    each of said plurality of processing units broadcasting operations received from one of said multiple others of said plurality of processing units to which it is coupled to one or more of said plurality of processing units.    
   
   
       13 . The method of  claim 12 , wherein: 
 said providing comprises providing said plurality of processing units disposed within a plurality of processing nodes each including multiple processing units, wherein within each processing node, each processing unit is coupled to each other processing unit within that processing node by a respective point-to-point communication link; and    said broadcasting comprises at least one processing unit in each processing node transmitting operations via a point-to-point communication link to a processing unit in a different processing node.    
   
   
       14 . The method of  claim 13 , wherein said transmitting comprises no more than one processing unit in each processing node transmitting operations to a processing unit in a given other processing node.  
   
   
       15 . The method of  claim 14 , wherein: 
 each point-to-point communication link coupling processing units within said plurality of processing nodes comprises a first tier link;    each point-to-point communication link coupling processing units in different processing nodes comprises a second tier link; and    said providing comprises providing a data processing system in which processing units coupled by said first tier links all follow a first uniform connectivity rule and processing units coupled by said second tier links all follow a second uniform connectivity rule.    
   
   
       16 . The method of  claim 12 , and further comprising: 
 reconfiguring the data processing system from a first configuration to a second configuration during operation of the data processing system without interrupting communication of operations between processing units in the second configuration.    
   
   
       17 . The method of  claim 1 , wherein said reconfiguring comprises coupling one or more additional processing units to the data processing system.