Scheduled Protocol Programming

Kasper Dokter

promotores: prof. dr. F. Arbab (UL)
and prof.dr. M.M. Bonsangue (UL)
Leiden University
Date: 24 May 2023
Thesis: PDF


With the advent of multicore processors and data centers, computer hardware has become increasingly parallel, allowing one to run multiple pieces of software at the same time on different machines. Coordination of these pieces is best expressed in a coordination language as an explicit interaction protocol that clearly defines the interactions among all components in the software.

An explicit interaction protocol not only improves code structure but also
enables automated analysis of the protocol to improve execution efficiency of the software. In this thesis, we focus in particular on improving execution efficiency by means of scheduling, which concerns with the allocation of (computing) resources to software tasks. Almost always, scheduling is the responsibility of a general-purpose operating system that makes no
assumptions on the software and thereby ignores all relevant scheduling information in that software. As a result, the operating system alone cannot ensure optimally scheduled execution of the software.

In this thesis, we propose a solution that changes the software such that it will be efficiently scheduled by the general-purpose operating system. The main idea is to take advantage of the duality between scheduling and coordination. To be precise, we analyze the protocol of the software to determine an optimal scheduling strategy for this software. Then, we enforce this optimal schedule by incorporating the strategy in the original protocol. As a result, we force the ignorant operating scheduler to follow our
precomputed optimal schedule.