US 11,748,280 B2
Broadcast scope selection in a data processing system utilizing a memory topology data structure
Michael S. Siegel, Raleigh, NC (US); and Guy L. Guthrie, Austin, TX (US)
Assigned to International Business Machines Corporation, Armonk, NY (US)
Filed by INTERNATIONAL BUSINESS MACHINES CORPORATION, Armonk, NY (US)
Filed on Aug. 4, 2021, as Appl. No. 17/394,117.
Prior Publication US 2023/0053882 A1, Feb. 23, 2023
Int. Cl. G06F 13/40 (2006.01); G06F 13/16 (2006.01)
CPC G06F 13/1668 (2013.01) [G06F 13/4027 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method of data processing in a coherent data processing system including a system fabric communicatively coupling a plurality of nodes arranged in a plurality of groups, wherein a plurality of coherence agents distributed among the nodes are assigned responsibility for certain addresses, said method comprising:
maintaining a topology data structure indicating, by group and node, differing physical locations within the data processing system of the plurality of coherence agents, wherein:
the topology data structure includes a plurality of entries each associated with a respective one of a plurality of values of an index portion of a request address; and
each of the plurality of entries includes a field including one or more bits for indicating group membership and one or more bits for indicating node membership;
a master in the data processing system accessing one of the plurality of entries in the topology data structure utilizing the index portion of the request address to obtain a particular group and particular node of a particular coherence agent among the plurality of coherence agents uniquely assigned the request address; and
based on the accessing, the master initially issuing, on the system fabric, a memory access request specifying the request address and utilizing a remote scope of broadcast that includes the particular node and excludes at least one other node in the particular group, wherein the particular node is a different one of the plurality of nodes than a home node containing the master.