Papers - Tokuda, Hideyuki

Scheduler 1-2-3: an interactive schedulability analyzer for real-time systems

Kotera-M, Tokuda-H

Proceedings COMPSAC 88    211-219 1988.10

Joint Work, Accepted

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Scheduler 1-2-3 is an interactive analysis tool that can perform schedulability analysis for the development of real-time computing systems. The schedulability analysis can verify whether all hard real-time tasks in a target system will be completed by their deadlines at the system design phase. Scheduler 1-2-3 is a window-based stand-alone tool that can also be used as a synthetic workload generator in an integrated tool set that consists of a timing tool, a schedulability analyzer, and a real-time monitor/debugger.

A real-time monitor for a distributed real-time operating system

H. Tokuda, M. Kotera, and C. W. Mercer

SINGPLAN-Notice 24 ( 1 ) 68-77 1988.05

Joint Work, Accepted

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In this paper, we first address the issues in real-time monitoring and debugging, such as capturing the timing error, the monitor's invasive nature and visualization of system behavior. We then describe the architecture of the ART Real-Time　Monitor which is being built for a distributed real-time OS, called ARTS. The built-in monitoring/debugging kemel primitives are also mentioned.

Implementation of a time-driven scheduler for real-time operating systems

Hideyuki Tokuda., J.W. Wendorf, and H.Y. Wang

Proceedings of 8th IEEE Real-Time Systems Symposium    271-280 1987.12

Joint Work, Accepted

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In the time-driven scheduling (TDS) model, both the importance value and timing criticality of each task are given together as a function of time. The TDS scheduler attempts to maximize the total value of completed tasks. A practical TDS model that has been implemented in the Mach operating system kernel is described. Some of the important design considerations for a flexible TDS scheduler are discussed, with emphasis on policy/mechanism separation as a system structuring principle. The structure of a TDS scheduler that was actually implemented is explained. The practicality of the TDS scheduler is demonstrated by performance results.

Distributed Computing in a Network of 529 Type Workstation

In Proceedings of IEEE Workshop on Large Grain Parallelism, Providenc    ?? 1986.10

Single Work, Accepted

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In this paper, we describe the critical issues in providing a large grained parallel processing capability based on a network of powerful personal workstations. In particular, we address a policy problem where how an owner of the workstation can express 'willingness' for sharing. We also discuss a 'software' tastbed approach by which a program designer can improve construction of distributed software. 　　　　　　　　　　　　　

A time driven scheduling model for real-time operating system

E.D. Jensen, C.D. Locke, Hideyuki Tokuda

Proceedings IEEE Real-Time Sytems Symposium    112-122 1985.12

Joint Work, Accepted

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Process scheduling in real-time systems has almost invariably used one or more of three algorithms, namely, fixed priority, FIFO or round robin. The reasons for these choices are simplicity and speed in the operating system, but the cost to the system in terms of reliability and maintainability have not generally been assessed. The notion that the primary distinguishing characteristic of a real-time system is the concept that completion of a process or a set of processes has a value to the system which can be expressed as a function of time is discussed. This notion is described in terms of a time-driven scheduling model for real-time operating systems and provides a tool for measuring the effectiveness of most of the currently used process schedulers in real-time systems. Applying this model, a multiprocessor real-time system simulator was constructed with which a numberf well-known scheduling algorithms such as shortest process time, deadline, shortest slack time, FIFO and a fixed priority scheduler are measured with respect to the resulting total system values. This approach to measuring the process scheduling effectiveness is a first step in the longer term effort to produce a scheduler which will explicitly schedule real-time processes in such a way that their execution times maximize their collective value to the system, either in a shared-memory multiprocessing environment or in multiple nodes of a distributed processing environment.