An Efficient Real-Time Middleware Scheduling Algorithm for Periodic Real-Time Tasks

For real-time applications, the underlying operating system (OS) should support timely management of real-time tasks. However, most of current operating systems do not provide timely management facilities in an efficient way. There could be two approaches to support timely management facilities for real-time applications: (1) by modifying OS kernel and (2) by providing a middleware without modifying OS. In our approach, we adopted the middleware approach based on the TMO (Time-trigger Message-triggered Object) model which is a well-known real-time object model. The middleware, named TMSOM (TMO Support Middleware) has been implemented on various OSes such as Linux and Windows XP/NT/98. In this paper, we mainly consider TMOSM implemented on Linux (TMOSM/Linux). Although the real-time scheduling algorithm used in current TMOSM/Linux can produce an efficient real-time schedule, it can be improved for periodic real-time tasks by considering several factors. In this paper, we discuss those factors and propose an improved real-time scheduling algorithm for periodic real-time tasks. The proposed algorithm can improve system performance by making the structure of real-time middleware simpler.