Recently, a family of memory consistency protocols, called home-based protocol, was proposed as an alternative to the traditional lazy release consistency protocol. Under the home-based protocol, every page is assigned a home node, and every update made at non-home nodes is eagerly propagated to the home at lock release time. When updates are needed, they can be fetched from the home node with only one round trip message. It is more scalable than the traditional lazy release consistency protocol in several aspects. It uses fewer messages, has lower diff overhead, and requires smaller memory spaces.
But when it is implemented in page-based software distributed shared memory system, it has two main disadvantages. Namely, whole pages are fetched when pages are updated, and home assignment can affect the performance of system inadvertently.
To address these issues, I propose two improvements over the original home-base protocol. One is page slicing, which preserves information on the modified portion of a page and uses it to fetch only necessary portion of the page. The other is adaptive home assignment, which adaptively reassigns home of a page according to the guess of most beneficial home location.
