Sunday 2 March 2008

Clarification: Invalidation Policies

I skimmed through the original paper by Michael Scott "Sequential Specification of Transactional Memory Semantics", which introduced classification of invalidation policies (lazy, eager W-R, mixed and eager), that was a stumbling block at our last reading.

Apparently our understanding of what was meant turns out to be correct: Scott introduces a notion of transactional memory history as essentially a sequence of events which include reading and writing memory and commiting and aborting transactions (each event is annotated with a transaction), that he says that predicate C(H,s,t) (where H is a history and s and t are transactions) is a conflict function if C(H,s,t) satisfies certain rules (mainly asserting that non-overlapping transactions do not conflict), and then he classifies conflict functions into lazy, eager W-R, mixed or eager depending on what kind of histories particular conflict function classifies as a conflict.

No comments: