Building Portable Thread Schedulers for Hierarchical Multiprocessors: the BubbleSched Framework

TL;DR

This paper introduces BubbleSched, a flexible framework enabling experts to create and experiment with customized, portable thread schedulers tailored for hierarchical multiprocessor architectures, improving application performance.

Contribution

The paper presents a new framework that allows development and testing of custom thread schedulers for hierarchical multiprocessors, addressing limitations of existing OS scheduling APIs.

Findings

Framework supports dynamic bubble distribution

Enables development of portable, customized schedulers

Improves application performance on hierarchical architectures

Abstract

Exploiting full computational power of current more and more hierarchical multiprocessor machines requires a very careful distribution of threads and data among the underlying non-uniform architecture. Unfortunately, most operating systems only provide a poor scheduling API that does not allow applications to transmit valuable scheduling hints to the system. In a previous paper, we showed that using a bubble-based thread scheduler can significantly improve applications' performance in a portable way. However, since multithreaded applications have various scheduling requirements, there is no universal scheduler that could meet all these needs. In this paper, we present a framework that allows scheduling experts to implement and experiment with customized thread schedulers. It provides a powerful API for dynamically distributing bubbles among the machine in a high-level, portable, and efficient way. Several examples show how experts can then develop, debug and tune their own portable bubble schedulers.