Intel® 64 and IA-32 Architectures Optimization Reference Manual

MULTICORE AND HYPER-THREADING TECHNOLOGYExample 8-13. Discovering the Affinity Masks for Sibling Logical ProcessorsSharing the Same Cache (Contd.)CacheIDBucket is an array of unique Cache_ID values. Allocate an arrayof NumStartedLPs count of entries in this array for the target cache level.CacheProcessorMask is a corresponding array of the bit mask of logicalprocessors sharing the same target level cache, these are logicalprocessors with the same Cache_ID.The algorithm below assumes there is symmetry across the modularboundary of target cache topology if more than one socket is populatedin an MP system, and only the topology of the target cache level is discovered.Topology of other cache level can be determined in a similar manner.// Bucket Cache IDs and compute processor mask for the target cache of every package.CacheNum = 1;CacheIDBucket[0] = CacheID[0];ProcessorMask = 1;CacheProcessorMask[0] = ProcessorMask;}If (CacheID[ProcessorNum] == CacheIDBucket[i]) {CacheProcessorMask[i] |= ProcessorMask;Break; //Found in existing bucket,skip to next iteration.}For (ProcessorNum = 1; ProcessorNum < NumStartedLPs; ProcessorNum++) {ProcessorMask