Formalization of Habanero phasers using Coq

Phasers pose an interesting synchronization mechanism that generalizes many collective synchronization patterns seen in parallel programming languages, including barriers, clocks, and point-to-point synchronization using latches or semaphores. This work characterizes scheduling constraints on phaser operations, by relating the execution state of two tasks that operate on the same phaser. We propose a formalization of Habanero phasers, May-Happen-In-Parallel, and Happens–Before relations for phaser operations, and show that these relations conform with the semantics. Our formalization and proofs are fully mechanized using the Coq proof assistant, and are available online.