Page Access Count

The operating system needs page access history for swapping. However it can only be approximated by clearing access bit in page table entry periodically. With HMTT, each off-chip memory access can be captured online. Thus infact we can get a detailed access history page by page.

There remains a problem for HMTT to transfer the history information back to the host. The gigabit ethernet port can be used for this purpose. There will be micro-seconds level delay but is enough for OS to make decision.

We have used this technology in our research on page de-duplicationin KVM . Please see:

Licheng Chen, Zhipeng Wei, Zehan Cui, Mingyu Chen, Haiyang Pan, Yungang Bao,“CMD: Classification-based Memory Deduplication through Page Access Characteristics”,the 10th ACM SIGPLAN/SIGOPS International Conference on Virtual Execution Environments(VEE14),Salt Lake City, UT,March 1-2,2014