Methods of cache preloading on a partition or a context switch

A method for operating a computing system, said method comprising:

• providing a computing system comprising:
• a processor, and wherein a plurality of virtual computing systems operate on the processor;
• a cache in communication with said processor;
• a main memory in communication with said cache;
• and
• a region-based cache prefetcher for preloading the cache for the virtual systems, including grouping blocks of the cache into regions of the main memory, and when each of the virtual systems executes, identifying one or more of said regions for prefetching from the main memory and into the cache based on previous accesses by said each virtual system to the cache;
• the region-based cache prefetcher comprising a region access table (RAT) configured to track access of memory blocks in said main memory, wherein said RAT comprises a plurality of RAT entries, and each of said RAT entries comprises a region group identifier and a block presence vector;
• upon an access of said cache by said processor for data in a byte in a block of a region including plurality of memory blocks and located within said main memory, storing region group identifier bits that identify said region in a region group identifier of a selected RAT entry among said plurality of RAT entries;
• upon said access of said cache, storing block presence identifier bits that identify at least one block among said plurality of memory blocks in a block presence vector of said selected RAT entry, wherein a bit of said block presence vector represents said block;
• and
• the region-based cache prefetcher tracking cache hits during operation of each of the virtual computing systems to identify regions of the main memory where at least one cache block has had a cache hit during said operation of said each virtual computing system, and the region-based cache prefetcher only prefeteching memory blocks from the identified regions of the main memory for the each virtual operating system.