Stochastic feedback-based control of QoS in soft real-time systems

This paper investigates application of feedback based control mechanisms to the problem of scheduling soft real-time tasks on a shared CPU. Each task has an execution time stochastically varying in time and it has to be provided with a specified level of Quality of Service (QoS). The problem of feedback control is formalised in the stochastic domain, by expressing QoS requirements in terms of properties to be satisfied by the stochastic process describing the evolution of the system state. We present several control schemes and address the fundamental problem of stochastic stability. Experimental results collected by a modified version of the Linux operating system show the effectiveness of the approach and its practical feasibility.

[1]  Giorgio C. Buttazzo,et al.  Adaptive bandwidth reservation for multimedia computing , 1999, Proceedings Sixth International Conference on Real-Time Computing Systems and Applications. RTCSA'99 (Cat. No.PR00306).

[2]  Shuichi Oikawa,et al.  Resource kernels: a resource-centric approach to real-time and multimedia systems , 2001, Electronic Imaging.

[3]  Jonathan Walpole,et al.  Analysis of a reservation-based feedback scheduler , 2002, 23rd IEEE Real-Time Systems Symposium, 2002. RTSS 2002..

[4]  James H. Anderson,et al.  Proportional share scheduling of operating system services for real-time applications , 1998, Proceedings 19th IEEE Real-Time Systems Symposium (Cat. No.98CB36279).

[5]  Tatsuo Nakajima.  Resource Reservation for Adaptive QOS Mapping in Real-Time Mach , 1998, IPPS/SPDP Workshops.

[6]  Sanjoy K. Baruah,et al.  Greedy reclamation of unused bandwidth in constant-bandwidth servers , 2000, Proceedings 12th Euromicro Conference on Real-Time Systems. Euromicro RTS 2000.

[7]  Klara Nahrstedt,et al.  A control theoretical model for quality of service adaptations , 1998, 1998 Sixth International Workshop on Quality of Service (IWQoS'98) (Cat. No.98EX136).

[8]  Robert C. Daley,et al.  An experimental time-sharing system , 1962, AIEE-IRE '62 (Spring).

[9]  Christos G. Cassandras,et al.  Introduction to Discrete Event Systems , 1999, The Kluwer International Series on Discrete Event Dynamic Systems.

[10]  Giuseppe Lipari,et al.  A bandwidth reservation algorithm for multi-application systems , 1998, Proceedings Fifth International Conference on Real-Time Computing Systems and Applications (Cat. No.98EX236).

[11]  Antonio Bicchi,et al.  Quality of service control in soft real-time applications , 2003, 42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475).

[12]  Sang Hyuk Son,et al.  Performance specifications and metrics for adaptive real-time systems , 2000, Proceedings 21st IEEE Real-Time Systems Symposium.

[13]  Stefan Savage,et al.  Processor Capacity Reserves for Multimedia Operating Systems , 1993 .

[14]  Tommaso Cucinotta,et al.  Adaptive reservations in a Linux environment , 2004, Proceedings. RTAS 2004. 10th IEEE Real-Time and Embedded Technology and Applications Symposium, 2004..

[15]  O. Hernández-Lerma,et al.  Markov chains and invariant probabilities , 2003 .

[16]  Calton Pu,et al.  A feedback-driven proportion allocator for real-rate scheduling , 1999, OSDI '99.

[17]  Dickon Reed,et al.  Nemesis, The Kernel - Overview , 1997 .

[18]  Giorgio C. Buttazzo,et al.  Integrating multimedia applications in hard real-time systems , 1998, Proceedings 19th IEEE Real-Time Systems Symposium (Cat. No.98CB36279).

[19]  John Regehr,et al.  Augmented CPU reservations: towards predictable execution on general-purpose operating systems , 2001, Proceedings Seventh IEEE Real-Time Technology and Applications Symposium.

[20]  Luigi Palopoli,et al.  On the Application of Hybrid Control to CPU Reservations , 2003, HSCC.