1. A computer implemented method for maintaining cache coherency in a processor system comprising a first node, the first node comprising a first plurality of central processor (CP) clusters, each CP cluster comprising a second plurality of processors, each CP cluster having a respective local cache shared by processors of the respective CP cluster, the processor system configured to perform a multi-tiered cache coherency protocol, the multi-tiered cache coherency protocol consisting of any one of local cache coherency operations within a node and global cache coherency operations between nodes, wherein cache coherency operations consist of any one of finding a cache line, obtaining a cache line and updating coherency state of a cache line, the computer implemented method comprising: for each cache line installed in a CP cluster of a node, designating one CP cluster of the node as a local intervention master (LIM) CP cluster for the respective cache line, the LIM CP cluster of a respective cache line being the CP cluster of the node having the most recently installed copy of the respective cache line, wherein a LIM CP cluster of a respective cache line is a designated point of coherency for the respective cache line; initiating a first cache request for access to a first cache line, by a first processor of a first CP cluster of the first node; based on the first cache line being not available in a local cache of the first CP cluster, broadcasting the first cache request, over a local fabric, to other CP clusters, the other CP clusters comprising a local intervention master (LIM) CP cluster of the first cache line; based on the first cache request, performing a first cache coherency operation, between the first CP cluster and a designated LIM CP cluster of the first cache line; and based on the first cache coherency operation causing the first cache line to be installed in a local cache of the first CP cluster, designating, by the processor system, the first CP cluster as LIM CP cluster of the first cache line.