US Patent 11593109 Sharing instruction cache lines between multiple threads

Aspects are provided for sharing instruction cache footprint between multiple threads using instruction cache set/way pointers and a tracking table. The tracking table is built up over time for shared pages, even when the instruction cache has no access to real addresses or translation information. A set/way pointer to an instruction cache line is derived from the system memory address associated with a first thread's instruction fetch. The set/way pointer is stored as a surrogate for the system memory address in both an instruction cache directory (IDIR) and a tracking table. Another set/way pointer to an instruction cache line is derived from the system memory address associated with a second thread's instruction fetch. A match is detected between the set/way pointer and the other set/way pointer. The instruction cache directory is updated to indicate that the instruction cache line is shared between multiple threads.