Abstract: Miss rate curves are constructed in a resource-efficient manner so that they can be constructed and memory management decisions can be made while the workloads are running. The resource-efficient technique includes the steps of selecting a subset of memory pages for the workload, maintaining a least recently used (LRU) data structure for the selected memory pages, detecting accesses to the selected memory pages and updating the LRU data structure in response to the detected accesses, and generating data for constructing a miss-rate curve for the workload using the LRU data structure. After a memory page is accessed, the memory page may be left untraced for a period of time, after which the memory page is retraced.

Abstract: Updating contents of certain memory pages in a virtual machine system is deferred until they are needed. Specifically, certain page update operations are deferred until the page is accessed for a load or store operation. Each page within the virtual machine system includes associated metadata, which includes a page signature characterizing the contents of a corresponding page or a reference to a page with canonical contents, and a flag that indicates the page needs to be updated before being accessed. The metadata may also include a flag to indicate that a backing store of the memory page has contents of a known content class. When such a memory page is mapped to a shared page with contents of that known content class, a flag in the metadata to indicate that contents of the memory page needs to be updated is not set.

Abstract: Page data of a virtual machine is represented for efficient save and restore operations. One form of representation applies to each page with an easily identifiable pattern. The page is described, saved, and restored in terms of metadata reflective of the pattern rather than a complete page of data reflecting the pattern. During a save or restore operation, however, the metadata of the page is represented, but not the page data. Another form of representation applies to each page sharing a canonical instance of a complex pattern that is instantiated in memory during execution, and explicitly saved and restored. Each page sharing the canonical page is saved and restored as a metadata reference, without the need to actually save redundant copies of the page data.