User-mode Scheduling (UMS)

1. Introduction

• User-mode scheduling (UMS) is a lightweight mechanism that applications can use to schedule their own threads [1].
  • It allows the programmer of a C user space application to schedule threads without involving the kernel scheduler.
  • The overview of the mechanism is described by Dave Probert in [4] or can be found by searching for his interview on Microsoft Learn [5], since his interview from Channel 9 was moved there [6].
• The project was implemented based on specifications described in [2].

2. Design

• The design was inspired by Dave Probert’s interview [4] and the patent for UMS on Windows [7]: