Details of a Researcher - Tokuda, Hideyuki

Papers - Tokuda, Hideyuki

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Comprehensive operating system for highly parallel machine

Saito-N; Hagino-T; Oikawa-S; Yonezawa-A; Matsuoka-S; Inohara-S; Tada-Y; Sunahara-H; Ishii-S; Shibayama-E; Shinoda-Y; Tokuda-H

In Proceedings of the 1994 International Symposium on Parallel Architectures, Algorithms and Networks (ISPAN) 435-442 1994

Joint Work, Accepted

This paper describes the design and implementation of a comprehensive operating system (COS) for highly parallel machine. This is one of the research themes in the Japanese University Highly Parallel Research Project supported by the Special Grant of the Research Funds of Ministry of Education. The target machine is called JUMP-1 originally developed in this project. Several design policies are discussed, and the user service classes are defined. COS architecture is based on the micro kernel, and it includes both Partition OS and Service OS. The development environment is also discussed briefly

Integrated Management of Priority Inversion in Real-Time Mach

T. Nakajima, T.Kitayama, H. Arakawa, H. Tokuda

In Proceedings of 14th IEEE Real-Time Systems Symposium 120-130 1993.12

Joint Work, Accepted

Synchronization and communication are two common sources of priority inversion which may make the behavior of systems unpredictable and unanalyzable. In microkernel-based systems, they are heavily used for building operating system servers and decomposing applications into several tasks. The management of priorities in IPC and synchronization should be integrated using a uniform mechanism since priority inversion occurs if such integration is not supported. Also, a highly preemptable server structure should be provided because the execution in a server may take up too much time. In this paper, we propose an integrated real-time resource management model, and a real-time server model which solve the above problems. We implemented and evaluated the models in Real-Time Mach using a uniform mechanism. Our approach enables us to build operating system servers and to decompose applications into several tasks without incurring priority inversion.

Dynamic QOS Control based on RealTime Threads

Kitayama, T, Tokuda, H

Proc. Fourth International Workshop on Network and Operating System Support for Digital Audio and Video 114-123 1993.10

Joint Work, Accepted

Processor capacity reserves: An abstraction for managing processor usage

C. W. Mercer, S. Savage, H. Tokuda

In Proc. Of the 4th Workshopon Workstation Operating Systems (WWOS-IV) 129-134 1993.10

Joint Work, Accepted

This paper briefly motivates and describes processor capacity reserves and a prototype implementation of reserves in Real Time Mach. The reservation mechanism provides a way for application programs to specify their reservation requests and incorporates a scheduling framework which supports an admission control policy. The reservation system accurately measures processor usage of individual threads, even when these threads invoke user-level servers to do work on their behalf, and the scheduler enforces reservations by relegating reserves to a time-sharing pool after their reservations have been consumed.

RT-IPC: An IPC Extension for Real-Time Mach

Takuro Kitayama, T.Nakajima, H. Tokuda

In Proceedings of the 2nd Microkernel and Other Kernel Architectures 91-104 1993.09

Joint Work, Accepted

Interprocess communication (IPC) provides the fundamental mechanism for the Mach microkernel to be extensible and flexible. Mach IPC provides efficient communication mechanisms for many applications. However, it does not provide sufficient functionality for real-time applications which have rigid timing constraints among threads. In Real-Time Mach (RT-Mach), we have extended Mach IPC to be priority inversion free for real-time applications. This paper describes the Real-Time IPC (RT-IPC) facilities, its implementation, and the evaluation results. We used the Distributed Hartstone (DHS) real-time benchmark for the evaluation and the results show that RT-IPC can reduce priority inversion and improve CPU utilization for real-time applications.

Continuous Media Communication with Dynamic QOS Control Using ARTS with an FDDI Network

Y. Tobe, S. T. C. Chou, and J. M. F. Moura, H. Tokuda

Proceedings of the ACM SIGCOMM'92 Symposium on Communications Architectures and Protocols 88-98 1992.10

Joint Work, Accepted

Continuous media communication requires timely delivery of data such as digital video and audio packets. Quality of Service (QOS) parameters specify the temporal and spatial characteristic of such continuous media data. To insure timely delivery of continuous media data, the system needs to minimize the communication delay by securing required processor and network resources. We have extended the Capacity-Based Session Reservation Protocol(CBSRP), which was proposed to realizing predictable real-time communications, to support dynamic control of QOS. We have implemented a QOS control scheme by which the network dynamically adjusts the allocations of network bandwidth on a Fiber Distributed Data Interface(FDDI) network. In this paper, we describe the definition of our QOS model, the extension of CBSRP to support dynamic control of QOS, and the implementation and evaluation of extended CBSRP in our distributed systems testbed, Advanced Real-Time System(ARTS).

An object-oriented real-time programming language

Y. Ishikawa, C. W. Mercer, H.Tokuda

IEEE Computer 25 ( 10 ) 66-73 1992.10

Joint Work, Accepted

Microkernel operating system architecture and Mach

D.L. Black, D. B. Golub, D.P. Julin, R.F. Rashid, R. P. Draves, R. W. Dean, A. Florin, J. Barrera, G. Malan, and D. Bohman, H. Tokuda

In Proceedings of theUsenix Workshop on Microkernels and Other Kernel Architectures 11-31 1992.10

Joint Work, Accepted

Modular architectures based on a microkernel are suitable bases for the design and implementation of operating systems. Prototype systems employing microkernel architectures are achieving the levels of functionality and performance expected and required of commercial products. Researchers at Carnegie Mellon University, the Open Software Foundation, and other sites are investigating implementations of a number of operating systems that use the Mach microkernel. The paper describes the Mach microkernel, its use to support implementations of other operating systems, and the status of these efforts.

Evaluation of realtime synchronization in Real-Time Mach

H. Tokuda, T. Nakajima

In Proc. Of the Second Mach Symposium 213-221 1991.10

Joint Work, Accepted

Real-Time Mach provides real-time thread and real-time synchronization facilities. A real-time thread can be created for a periodic or aperiodic activity with a timing constraint. Threads can be synchronized among them using a real-time version of the monitor-based synchronization mechanism with a suitable locking protocol. Real-time Mach has several locking policies, such as kernelized monitor, basic priority priority inheritance protocol, priority ceiling protocol, and restartable critical section, for real-time applications. It can also avoid an unbounded priority inversion problem. The authors describe the real-time synchronization facilities in Real-Time Mach and its implementation and performance evaluation. The evaluation results demonstrated that a proper choice of locking policy can avoid unbounded priority inversions and improve the processor schedulability for real-time applications.

Microkernel operating system architecture and Mach

Black-DL; Golub-DB; Julin-DP; Rashid-RF; Draves-RP; Dean-RW; Forin-A; Barrera-J; Malan-G-R; Bohman-D, Tokuda-H

Journal-of-Information-Processing 14,4 442-453 1991

Joint Work, Accepted

Modular architectures based on a microkernel are suitable bases for the design and implementation of operating systems. Prototype systems employing microkernel architectures are achieving the levels of functionality and performance expected and required of commercial products. Researchers at Carnegie Mellon University, the Open Software Foundation, and other sites are investigating implementations of a number of operating systems (e.g., Unix, MS-DOS) than use the Mach microkernel. The paper describes the Mach microkernel, its use to support implementations of other operating systems, and the status of these efforts.

Fixed Priority Scheduling Theory for Hard Real-Time Systems,

J. P. Lehoczky, L. Sha, J. K. Strosnider, H. Tokuda

in Foundations of Real-Time Computing, Scheduling and Resource Management (A. M. Tilborg and G. M. Koob, eds.), ch. 1 chap 1 1-30 1991

Joint Work

An Evaluation of Priority Consistency in ProtocolArchitectures

Clifford W. Mercer, Hideyuki Tokuda

In Proceedings of the IEEE 16th Conference on Local Computer Networks 386-396 1991

Joint Work, Accepted

Workstations for digital audio and video applications must support predictable processing, presentation, and transmission of continuous media data while making efficient use of limited hardware resources. The authors present techniques for managing network resources and processing messages in a predictable fashion. Their solutions use a novel structure for the protocol processing software, and they examine several alternatives and discuss the engineering tradeoffs associated with each. Using simulation, they evaluate their protocol processing structures and show that the more sophisticated structures can improve the response time and predictability of time-constrained messages. The ideas presented in this paper can be applied to resource management in the operating system and to the structuring of application-level servers. The designers of gateway machines (for internetwork routing) which handle both time-constrained traffic and non-time-constrained traffic may also benefit from this study.

The ARTS Real-Time Object Model

Clifford W. Mercer, Hideyuki Tokuda

Proceedings of the 11th Real-Time Systems Symposium, 2-10 1990.12

Joint Work, Accepted

In this paper, we present the motivation for using object model for real-time operating systems and we describe the object model used in the ARTS Kernel, a real-time operating system developed in the ART project at Carnegie Mellon University. We discuss our novel object classification and the priority inheritance properties which arise from this taxonomy. We also discuss various methods for implementing critical regions and give some guidelines as to the use of each. 　　　　　　　

Distributed Hartstone: a distributed real-time benchmark suite

Y. Ishikawa,C. W. Mercer, H. Tokuda

Proceedings. The 10th International Conference on Distributed Computing Systems 70-77 1990.10

Joint Work, Accepted

An extension of the uniprocessor Hartstone benchmark for the distributed real-time environment, called the Distributed Hartstone benchmark, is described. The Distributed Hartstone measures system performance in the critical areas of communication latency and bandwidth, protocol preemptability, and priority queueing at the protocol and media access levels. Areas of the system which are particularly important for distributed, real-time computing are described. On the basis of the requirements that specify various areas of the system that a distributed real-time benchmark must stress, a series of task sets in the style of the Hartstone benchmarks are given. The benchmark results from a distributed real-time operating system (ARTS testbed) are given

Object-oriented real-time language design: constructs for timing constraints

Y. Ishikawa,C. W. Mercer, H. Tokuda

In Proc. Of ECOOP/OOPSLA 289-298 1990.10

Joint Work, Accepted

We propose a new object-oriented programming language called RTC++ for programming real-time applications. RTC++ is an extension of C++ and its features are to specify I) a real-time object which is an active entity, ii) timing constraints in an operation as well as in statements, and iii) a periodic task with rigid timing constraints. In this paper, we first discuss real-time programming issues and what language support should be provided for building real-time applications. Then, the key features of RTC++ are described. Some programming examples are shown to demonstrate RTC++'s expressive power. A comparison to other programming languages are also discussed.

Real-Time Mach: Towards a Predictable Real-Time System

H. Tokuda, T. Nakajima, P. Rao

In Proceedings of USENIX Mach Workshop 73-82 1990.10

Joint Work, Accepted

Distributed real-time systems play a very important role in our modern society. They are used in aircraft control, communication systems, military command and control systems, factory automation, and robotics. However, satisfying the rigid timing requirements of various real-time activities in distributed real-time systems often requires ad hoc methods to tune the system's runtime behavior The objective of Real-Time Mach is to develop a realtime version of the Mach kernel which provides users with a predictable and reliable distributed real-time computing environment. In this paper, we describe a real-time thread model, real-time synchronization, and the ITDS scheduler in Real-Time Mach. We also discuss the implementation issues, a real-time toolset, and the current status of the system.

Mach: a system software kernel

Rashid-RF, Tokuda-H

Computing-Systems-in-Engineering 1,2-4 163-169 1990.04

Joint Work, Accepted

Priority inversions in real-time communication

H. Tokuda, C. W. Mercer, Y. Ishikawa, T. E. Marchok

In Proceedings of 10th IEEE Real-Time Systems Symposium 348-359 1989.12

Joint Work, Accepted

ARTS: A distributed real-time kernel

H. Tokuda, C. W. Mercer

ACM Operating Systems Review 23 ( 3 ) 29-53 1989.07

Joint Work, Accepted

ARTS is a distributed real-time operating system designed for a real-time systems testbed being developed at Carnegie Mellon University. The objective of the testbed is to develop and verify advanced real-time computing technologies for a distributed environment. The paper gives an overview of the ARTS kernel and ARTS real-time toolset. In particular, it introduces a real-time object model and the integrated time-driven scheduling model. It then describes the basic primitives and major components of the ARTS kernel and the real-time toolset which consists of the schedulability analyzer, Scheduler 1-2-3, and real-time monitor/debugger, ARM.

A real-time tool set for the ARTS kernel

Tokuda. H, M. Kotera

Proceedings of 9th IEEE Real-Time Systems Symposium 289-299 1988.12

Joint Work, Accepted

An integrated real-time tool set is described that consists of a schedulability analyzer and a real-time monitor/debugger for the ARTS kernel, which is being built for a distributed real-time testbed. The schedulability analyzer, called Scheduler 1-2-3, is an X11 window-based interactive tool and can verify whether the given real-time tasks can meet their deadlines under a specific scheduling policy. An advanced real-time monitor, ARM, also runs on the X11 window and visualizes the target system's runtime behavior in real time. ARM can be used with Scheduler 1-2-3 to analyze simulated runs and its monitorability

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