A scheme for scheduling hard real-time applications in open system environment

Abstract

This paper focuses on the problem of providing runtime support to real-time applications and non-real-time applications in an open system. It describes a two-level hierarchical priority-driven scheme for scheduling independently developed applications. The scheme allows the developer of each real-time application to validate the schedulability of the application independently of other applications. Once a r eal-time application is created and accepted by the open system, its schedulability is guaranteed r egardless of the behaviors of other applications that execute concurrently in the system.

Virtual-CPU Scheduling in the Quest Operating System

“…CBS guarantees a total utilization factor no greater than Q s /T s , even in overloads, by specifying a maximum budget in a designated window of time. This contrasts with work on the Constant Utilization Server (CUS) [6] and Total Bandwidth Server (TBS) [24], which ensure bandwidth limits only when actual job execution times are no more than specified worst-case values. CBS has bandwidth preservation properties similar to that of the Dynamic Sporadic Server (DSS) [7] but with better responsiveness.…”

Local Adjustment and Global Adaptation of Control Periods for QoC Management of Control Systems

“…A two-level pre-emptive scheduling model was described in which the global scheduler could be the EDF [25], [26]. A hierarchical scheme was proposed in [27], where an application-level feedback was used to adjust the QoC requirements of the control tasks and a system-level feedback was employed to adjust the bandwidths assigned to the tasks.…”

Untitled

“…The notions of best-effort and real-time processing have fractured into a spectrum of processing classes with different timeliness requirements including desktop multimedia, soft real-time, firm real-time, adaptive soft real-time, rate-based and traditional hard real-time [2][3]. Real Time systems may be Hard-real time where missing deadline is catastrophic or Soft-real time where, occasional violation of deadline may not result in useless execution of the application but decreases utilization [4].…”