A. framework for integrating the real-time specification for Java and Java's remote method invocation

Wellings, Andy; Clark, Raymond K.; Jensen, Douglas; Wells, Douglas M.

doi:10.1109/isorc.2002.1003655

Cited by 37 publications

(22 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also plan to carry out the analysis of the meta-event logical expression in order to generate the ReclamationCondition expression. Yet another perspective is to apply the reclamation algorithm to a distributed real-time Java environment such as DRTSJ [7], [8], [9].…”

Section: Discussionmentioning

confidence: 99%

Resource reclamation using meta-events in a real time java system

Curcio

Midonnet

2007

2007 International Conference on Parallel and Distributed Systems

View full text Add to dashboard Cite

The objective of this work is to optimize the behavior of a real-time java system, by identifying and then reaffecting resources which have been allocated to tasks but unused. The tasks in question are periodic tasks which produce aperiodic events such as exceptions. In a real-time system, guaranteeing the task response time leads to resource reservation (CPU, Memory) necessary to their execution. Resource reservation is nevertheless essential because the worst case scenario, where all events are produced at their maximum frequency, is the one that must be catered for. In many cases the worst case scenario never materialises and a part of the resources is wasted. The objective of this work is to present a reclamation mechanism for unused resources. This applies to asynchronous events which have not been activated and other events which we are certain will remain inactivated. An asynchronous event is, at the same time, an object (the AsyncEvent) and the associated handler of that object (AsyncEventHandler). A meta-event is an object used to specify the relationship between asynchronous events. It is this relationship which will enable us to predict the resources which will remain unused and can thus be reallocated. In this paper we will discuss three points. What quantity of resources can be saved from each task ? When can they be collected and for how long will they be available ?

show abstract

Section: Discussionmentioning

confidence: 99%

Resource reclamation using meta-events in a real time java system

Curcio

Midonnet

2007

2007 International Conference on Parallel and Distributed Systems

View full text Add to dashboard Cite

show abstract

“…One possible approach to include information is an extended manifest (see Listing 1). Bold lines correspond to a very simple real-time characterization scheme compatible with RTSJ (The RealTime Specification for Java) and DRTSJ [4] (The Distributed Specification for Java). The descriptor defines processing group parameters for each system resource; namely, the CPU allocated, the memory allocation rate required from the real-time garbage collector, and the messages sent using the network by the system.…”

Section: Rt-osgimentioning

confidence: 99%

Real-time distribution support for residential gateways based on OSGi

Val

García-Valls

Estévez-Ayres

2011

2011 IEEE International Conference on Consumer Electronics (ICCE)

View full text Add to dashboard Cite

show abstract

“…More recently, software/hardware co-design has found its place in real-time application development as well. Although exposed more frequently with uniprocessor platforms, software real-time systems can also be implemented on multi-processor platforms, distributed systems such as real-time CORBA [48] and distributed real-time Java [107] or even complex networked systems. Finally, one can find a system that combines several of the aforementioned real-time systems as its components.…”

Section: Firm Real-time Systemsmentioning

confidence: 99%

Garbage Collection for Flexible Hard Real-Time Systems

Chang

Wellings

2010

IEEE Trans. Comput.

View full text Add to dashboard Cite

Garbage collection is key to improving the productivity and code quality in virtually every computing system with dynamic memory requirements. It dramatically reduces the software complexity and consequently allows the programmers to concentrate on the real problems rather than struggling with memory management issues, which finally results in higher productivity. The code quality is also improved because the two most common memory related errors -dangling pointers and memory leaks -can be prevented (assuming that the garbage collectors are implemented correctly and the user programs are not malicious).However, real-time systems, particularly those with hard real-time requirements, always choose not to use garbage collection (or even dynamic memory) in order to avoid the unpredictable executions of garbage collectors as well as the chances of being blocked due to the lack of free memory. Much effort has been expended trying to build predictable garbage collectors which can provide both temporal and spatial guarantees. Unfortunately, most existing work leads to systems that cannot easily achieve a balance between temporal and spatial performance, although their worst-case behaviours in both dimensions can be predicted. Moreover, the real-time systems targeted by the existing real-time garbage collectors are not the state-ofthe-art ones. The scheduling of those garbage collectors has not been integrated into the modern real-time scheduling frameworks, which makes the benefits provided by those systems very difficult to obtain. This thesis argues that the aforementioned issues should be tackled by introducing new design criteria for real-time garbage collectors. The existing criteria are not enough to reflect the unique requirements of real-time systems. A new performance indicator is proposed to describe the capability of a real-time garbage collector to achieve better balance between temporal and spatial performance. Moreover, it is argued that new real-time garbage collectors should be integrated with the real-time task model and more advanced scheduling techniques should be adopted as well.A hybrid garbage collection algorithm, which combines both reference counting and mark-sweep, is designed according to the new design criteria. On the one hand, the reference counting component helps reduce the overall memory requirements. On the other hand, the mark-sweep component periodically identifies cyclic garbage, which cannot be found by the reference counting component. Both parts of the collector are executed by segregated tasks, which are released periodically as the hard real-time user tasks. In order to improve the performance of soft-or non-realtime tasks in our system while still guaranteeing the hard real-time requirements, the dual-priority scheduling algorithm is used for all the tasks including the GC tasks. A multi-heap approach is also proposed to bound the impacts of the softor non-real-time tasks on the overall memory usage as well as the executions of the GC tasks. More importantly, static ana...

show abstract

A. framework for integrating the real-time specification for Java and Java's remote method invocation

Cited by 37 publications

References 6 publications

Resource reclamation using meta-events in a real time java system

Resource reclamation using meta-events in a real time java system

Real-time distribution support for residential gateways based on OSGi

Garbage Collection for Flexible Hard Real-Time Systems

Contact Info

Product

Resources

About