Gill, Levine, and Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of TimeCritical Computing Systems 20(2), Kluwer, March 2001.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....all tasks can make their deadlines. Note that while designing and implementing a system that most changes made will affect the real time properties of the system. This makes real time scheduling a global cross cutting dependency. While many different schedulability analysis techniques exist [1, 2, 4, 9, 11, 16, 26], they differ in their assumptions on the task set and none of the existing analysis is applicable to all real time embedded systems. The compatibility between schedulability analyses and the characteristics of the designed system is a typical crosscutting dependency that is hidden from the ....

....to the system. However, if the same task set is designed on a distributed platform, the DM Offset analysis described below will be applied. 4.1. Deadline Monotonic with Phase Offset Currently the VEST scheduling tool implements the basic Rate Monotonic check, the Maximum Urgency First algorithm [4], and a more sophisticated end to end analysis for distributed systems. In applying the tool to a Boeing s distributed avionics case study we found that RMA and MUF were not sufficient because such systems often run on a distributed platform. Avionics based on real time CORBA (e.g. Bold Stroke ....

Gill, C., Levine, D. and Schmidt, D. (2000) The Design and Performance of a Real-Time CORBA Scheduling Service, Real-Time Systems, 20(2), Kluwer.

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Christopher D. Gill, David L. Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, to appear 2000.

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Christopher D. Gill, David L. Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, no. 2, Mar. 2001.

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Christopher D. Gill, David L. Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, no. 2, Mar. 2001.

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C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, Mar. 2001.

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C. Gill, D. Levine, and D. Schmidt, "The Design and Performance of a Real-time CORBA Scheduling Service," The International Journal of Time-Critical Computing Systems 20(2), Kluwer, March 2001.

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Gill C., Levine D., Schmidt, D. "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of TimeCritical Computing Systems 20(2), Kluwer, March 2001.

....distributed application components. Several kinds of middleware are emerging as fundamental building blocks for these kinds of systems. Low level frameworks such as ACE [20] provide portability across different operating systems and hardware platforms. Resource management frameworks such as Kokyu [6] use low level elements to configure scheduling and dispatching mechanisms in higher level middleware. Real Time ORBs such as TAO [21] and nORB [23] are geared toward providing predictable timing of end to end method invocations. ORB services such as the TAO Real Time Event Service [9] and TAO ....

....elements to configure scheduling and dispatching mechanisms in higher level middleware. Real Time ORBs such as TAO [21] and nORB [23] are geared toward providing predictable timing of end to end method invocations. ORB services such as the TAO Real Time Event Service [9] and TAO Scheduling Service [6] offer higher level services for managing functional and real time properties of interactions between application components. Finally, higher level middleware services such as RTARM [10] and QuO [29] provide integration of real time resource management in complex vertically layered DRE ....

C.D. Gill, D.L. Levine and D.C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems Journal, Special Issues on Real-Time Middleware, Vol. 20, No. 2, March 2001

....middleware that exposes mechanisms for the programmatic control of qualities of service. Recent advances in fundamental software technologies, such as aspect weaving software [2] and adaptive and reflec1 tive middleware, are beginning to provide the mechanisms described above. Adaptive middleware [3, 4, 5] is software whose functional and or quality of service (QoS) related properties can be modified either: Statically, e.g. to reduce footprint or to use and configure resources that can optimized in advance in deeply embedded systems or Dynamically, e.g. in response to changes in ....

....Communication resources are managed through the ability to specify protocol properties and by making explicit bindings to communication resources. Memory resources are managed through buffering requests and limiting thread pool sizes. A global scheduling service is also available [5]. In addition to RT CORBA, the CORBA Notification Service incorporates important QoS and filtering features into the previously defined CORBA Event Service. These middleware capabilities, appearing in an open specification that is independent of platform, OS, and vendor specific communication ....

[Article contains additional citation context not shown here]

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, March 2001.

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C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, March 2001.

....[24] and design constraints and tradeoffs, which transcends the present capabilities of COTS DOC middleware. Our prior research on CORBA middleware has explored the efficiency, predictability, scalability and dependability aspects of ORB endsystem design, including static [25] and dynamic [26] scheduling, event processing [9] I O subsystem [27] and pluggable protocol [28] integration, synchronous [29] and asynchronous [30] ORB Core architectures, systematic benchmarking of multiple ORBs [31] and optimization principle patterns for ORB performance [32] This paper extends our previous ....

Christopher D. Gill, David L. Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, no. 2, Mar. 2001.

....I O subsystems that lack advanced QoS features. 5. A real time resource scheduler: TAO s scheduler maps application QoS requirements, such as end to end latency or periodic deadlines, to ORB endsystem and network resources, such as CPU, primary and secondary storage, and network bandwidth [6, 64]. 6. A highly portable communication framework: TAO achieve a high degree of portability across platforms, TAO is developed using the ACE framework [65] which implements reusable C wrapper facades and framework components that support the QoS requirements of high performance, real time ....

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, March 2001.

....Having a real time ORB manage endsystem and communication resources only provides a partial solution. Real time CORBA ORBs must also preserve efficient, scalable, and predictable behavior endto end for higher level services and application components. For example, a global scheduling service [10, 27] can be used to manage and schedule distributed resources. Such a scheduling service can interact with an ORB to provide mechanisms that support the specification and enforcement of end to end operation timing behavior. Application developers can then structure their programs to exploit the ....

.... the RT CORBA specification permits a server application to define priority transforms that set the priority at which particular invocations are performed, e.g. based on external factors, such as current server load, operation criticality [10] or the state of a global scheduling service [27]. Transforms are implemented as hooks that are applied as requests are received or sent. A transform hook is passed the current CORBA priority and target object id and can change the invocation priority, potentially by calling out to application supplied code. The following two priority transform ....

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, 2000.

.... context switching, synchronization, dynamic memory allocation, and data movement [22] a highly scalable Object Adapter that demultiplexes requests in constant time [19] an optimizing IDL compiler [6] real time I O subsystem [9] and a global resource allocation and scheduling framework [21, 5]. CORBA protocol model synopsis: CORBA Inter ORB Protocols (IOP)s define interoperability between ORB endsystems. IOPs provide data representation formats and ORB messaging protocol specifications that can be mapped onto standard and or customized transport protocols. Regardless of the choice of ....

Christopher D. Gill, David L. Levine, and Douglas C. Schmidt. The Design and Performance of a Real-Time CORBA Scheduling Service. The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, 2000.

....constraints and tradeoffs, which transcends the present capabilities of commercial off the shelf (COTS) middleware. Our prior research on CORBA middleware has explored the efficiency, predictability, scalability and dependability aspects of ORB endsystem design, including static [10] and dynamic [11] scheduling, event processing [12] I O subsystem [13] and pluggable protocol [14] integration, synchronous [15] and asynchronous [16] ORB Core architectures, systematic benchmarking of multiple ORBs [17] optimization principle patterns for ORB performance [18] and high performance architectures ....

Christopher D. Gill, David L. Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware,vol. 20, no. 2, March 2001.

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Chris Gill, David Levine, and Douglas C. Schmidt, "The Design and Performance of a Real-time CORBA Scheduling Service," Real-time Systems, Kluwer, Vol. 20, No. 2, March, 2001.

....testbed utilizes four different thread priorities, which is representative of the fixed priority hard real time systems (such as avionics mission computing [26] for which Realtime CORBA 1.0 [2] was designed. Our future work on Realtime CORBA 2. 0 [27] is exploring dynamic scheduling capabilities [28] that handle a broader range of priorities. Operation invocation. The signature of the operation invoked by the client on the server is: void method (in unsigned long work) The work parameter specifies the amount of CPU intensive work the server will perform to service this invocation. The ....

....as CORBA. In this section, we compare our work on Real time CORBA and TAO with related work. Dynamic Scheduling Services and Resource Managers. Real time CORBA is well suited for applications using fixed priority scheduling. However, for applications that execute under dynamic load conditions [28] and cannot determine the priorities of various operations aprioriwithout significantly underutilizing various resources, the Object Management Group (OMG) is standardizing dynamic scheduling [29] techniques, such as deadline based [30] or value based [31] scheduling. Work is currently underway to ....

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, Mar. 2001.

....resources is hard; building them on time and within budget is even harder. A particularly essential task is supporting the quality of service (QoS) demands of mission critical DRE systems that possess a mix of hard and soft real time requirements, such as avionics mission computing systems [1], mission critical distributed audio video processing [2] 3] and real time robotic systems [4] B. Key Challenges: Flexibility and QoS Assurance DRE systems have historically been custom developed in an ad hoc and inflexible manner. While many operational systems have been built this way, ....

....performs best in all environments, which motivates our research in this paper on the design and performance of flexible scheduling frameworks for DRE middleware and applications. D. An Inclusive Solution: Multi paradigm Scheduling This paper extends our previous work on static [8] and dynamic [1] scheduling for Real time CORBA by incorporating a strategized scheduling framework called Kokyu as a service atop TAO. Kokyu enables the configuration and empirical evaluation of multiple scheduling paradigms, including: Static scheduling strategies, e.g. rate monotonic scheduling (RMS) ....

[Article contains additional citation context not shown here]

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, March 2001.

....applications [11] where priorities are assigned statically to tasks, and the task with the highest priority always runs. In many new and planned DRE applications, however, static task prioritization is often not possible, since task workloads and their priorities are not known until run time [12]. Although the Real time CORBA specification was integrated into the OMG standard several years ago, it has not yet been adopted universally for DRE applications, due to its # Steep learning curve, caused largely by the complexity of its C mapping, and # Run time and memory footprint ....

C. D. Gill, D. L. Levine, and D. C. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," Real-Time Systems, The International Journal of Time-Critical Computing Systems, special issue on Real-Time Middleware, vol. 20, March 2001.

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Gill, Levine, and Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of TimeCritical Computing Systems 20(2), Kluwer, March 2001.

No context found.

Gill, Levine, and Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of TimeCritical Computing Systems 20(2), Kluwer, March 2001.

No context found.

Gill, Levine, Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," RealTime Systems 20(2), Kluwer, March 2001.

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Chris Gill, David Levine, Douglas C. Schmidt, and Fred Kuhns. The Design and Performance of a Real-Time CORBA Scheduling Service. International Journal of Time-Critical Computing Systems special issue on Real-Time Middleware, to appear in 1999. 134

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Gill, Levine, and Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of Time-Critical Computing Systems 20(2), Kluwer, March 2001.

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C. Gill, D. Levine, D. Schmidt, "The Design and Performance of a Real-Time CORBA Scheduling Service," The International Journal of Time-Critical Computing Systems 20(2), Kluwer, March 2001.

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