An adaptive, distributed airborne tracking sysem

Clark, Raymond K.; Jensen, E. Douglas; Kanevsky, Arkady; Maurer, John A.; Wallace, Paul; Wheeler, Thomas M.; Zhang, Yun; Wells, Douglas M.; Lawrence, Tom; Hurley, Pat

doi:10.1007/bfb0097917

Cited by 42 publications

(30 citation statements)

References 1 publication

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such applications may have unpredictable task arrivals or non-deterministic execution times, which can cause permanent or transient overloads. Clark [40] and Welch [108] describe two distributed radar tracking systems which often must operate in overload, and suffer from non-deterministic execution times due to data-dependent processing and communication latencies incurred by their distributed structure. Both of their applications desire graceful performance degradation, and so require utility accrual scheduling [52], [39].…”

Section: Limitations Of Current Researchmentioning

confidence: 99%

An experimental evaluation of the scalability of real-time scheduling algorithms on large-scale multicore platforms

Dellinger

Lindsay

Ravindran

2012

ACM J. Exp. Algorithmics

View full text Add to dashboard Cite

This thesis studies the problem of experimentally evaluating the scaling behaviors of existing multicore real-time task scheduling algorithms on large-scale multicore platforms. As chip manufacturers rapidly increase the core count of processors, it becomes imperative that multicore real-time scheduling algorithms keep pace. Thus, it must be determined if existing algorithms can scale to these new high core-count platforms. Significant research exists on the theoretical performance of multicore real-time scheduling algorithms, but the vast majority of this research ignores the effects of scalability. It has been demonstrated that multicore real-time scheduling algorithms are feasible for small core-count systems (e.g. 8-core or less), but thus far the majority of the algorithmic research has never been tested on high core-count systems (e.g. 48-core or more).We present an experimental analysis of the scalability of 16 multicore real-time scheduling algorithms. These algorithms include global, clustered, and partitioned algorithms. We cover a broad range of algorithms, including deadline-based and utility accrual scheduling algorithms. These algorithms are compared under metrics including schedulability, tardiness, deadline satisfaction ratio, and utility accrual ratio. We consider multicore platforms ranging from 8 to 48 cores. The algorithms are implemented in a real-time Linux kernel we create called ChronOS. ChronOS is based on the Linux kernel's PREEMPT RT patch, which provides the underlying operating system kernel with real-time capabilities such as full kernel preemptibility and priority inheritance for kernel locking primitives. ChronOS extends these capabilities with a flexible, scalable real-time scheduling framework.Our study shows that it is possible to implement global fixed and dynamic priority and simple global utility accrual real-time scheduling algorithms which will scale to large-scale multicore platforms. Interestingly, and in contrast to the conclusion of prior research, our results reveal that some global scheduling algorithms (e.g. G-NP-EDF) is actually scalable on large core counts (e.g. 48). In our implementation, scalability is restricted by lock contention over the global schedule and the cost of inter-processor communication, rather than the global task queue implementation. We also demonstrate that certain classes of utility accrual algorithms such as the GUA class are inherently not scalable. We show that algorithms implemented with scalability as a first-order implementation goal are able to provide real-time guarantees on our 48-core platform.

show abstract

Section: Limitations Of Current Researchmentioning

confidence: 99%

An experimental evaluation of the scalability of real-time scheduling algorithms on large-scale multicore platforms

Dellinger

Lindsay

Ravindran

2012

ACM J. Exp. Algorithmics

View full text Add to dashboard Cite

show abstract

“…These include: (1) AWACS (Airborne WArning and Control System) surveillance mode tracker system [13] built by The MITRE Corporation and The Open Group (TOG); and (2) a coastal air defense system [14] built by General Dynamics (GD) and Carnegie Mellon University (CMU). We only summarize some of the application time constraints here; other details can be found in [13], [14], respectively.…”

Section: Motivating Application Examples For Tufsmentioning

confidence: 99%

Time/Utility Function Decomposition in Soft Real-Time Distributed Systems

Jensen¹

2004

View full text Add to dashboard Cite

We consider RealTime CORBA 2.0 (Dynamic Scheduling) distributable threads, whose time constraints are specified using time/utility functions (TUFs), operating in legacy environments. In legacy environments, system node resources-both physical (processor, disk, I/O, etc.) and logical (locks, etc.)-are shared among timecritical distributable threads and local applications that may or may not be timecritical. Thus, in such environments, distributable threads that are scheduled using their propagated TUFs and scheduling parameters, as mandated by RealTime CORBA 2.0's Case 2 approach, may suffer performance degradation, if a node scheduler can achieve higher local accrued utility by giving higher eligibility to local threads than to distributable threads.To alleviate this, we consider decomposing TUFs of distributable threads into "subTUFs" that are used for scheduling segments of distributable threads. We present methods for decomposing TUFs. Furthermore, we identify conditions under which TUF decomposition can alleviate perfor mance degradation. Our experimental results reveal that the most important factors that affect the performance of TUF decomposition include the properties of node scheduling algorithms, TUF shapes, task load, Global Slack F actor, local threads and resource dependencies, and that these factors interact.

show abstract

“…Embedded real-time systems that are emerging in many domains such as robotic systems in the space domain (e.g., NASA/JPL's Mars Rover [4]) and control systems in the defense domain (e.g., airborne trackers [2]) are fundamentally distinguished by the fact that they operate in environments with dynamically uncertain properties. These uncertainties include transient and sustained resource overloads due to context-dependent activity execution times and arbitrary activity arrival patterns.…”

Section: Chapter 1 Introductionmentioning

confidence: 99%

“…This is in contrast to deadlines, where a positive utility is accrued for completing the activity anytime before the deadline, after which zero, or infinitively negative utility is accrued. Control System (AWACS) built by The MITRE Corporation and The Open Group (TOG) [2] and (2) a battle management (BM)/command and control (C2) application built by General Dynamics (GD) and Carnegie Mellon University (CMU) [15]. Details of these applications can be found in [2] and [15], respectively; for brevity, they are omitted here.…”

Section: Chapter 1 Introductionmentioning

confidence: 99%

Utility Accrual Real-Time Scheduling under Variable Cost Functions

Balli¹,

Ravindran

et al. 2007

IEEE Trans. Comput.

Self Cite

View full text Add to dashboard Cite

We present a utility accrual real-time scheduling algorithm called CIC-VCUA, for tasks whose execution times are functions of their starting times. We model such variable execution times employing variable cost functions (or VCFs). The algorithm considers application activities that are subject to time/utility function time constraints (or TUFs), execution times described using VCFs, and concurrent, mutually exclusive sharing of non-CPU resources. We consider the multi-criteria scheduling objective of (1) assuring that the maximum interval between any two consecutive, successful completions of jobs of a task must not exceed a specified upper bound, and (2) maximizing the system's total accrued utility, while satisfying mutual exclusion resource constraints. Since the scheduling problem is intractable, CIC-VCUA statically computes worst-case sojourn times of tasks, selects tasks for execution based on their potential utility density, and completes them at specific times, in polynomialtime. We establish that CIC-VCUA achieves optimal timeliness during under-loads. Further, we identify the conditions under which timeliness assurances hold. Our simulation experiments illustrate CIC-VCUA's effectiveness and superiority.

show abstract

An adaptive, distributed airborne tracking sysem

Cited by 42 publications

References 1 publication

An experimental evaluation of the scalability of real-time scheduling algorithms on large-scale multicore platforms

An experimental evaluation of the scalability of real-time scheduling algorithms on large-scale multicore platforms

Time/Utility Function Decomposition in Soft Real-Time Distributed Systems

Utility Accrual Real-Time Scheduling under Variable Cost Functions

Contact Info

Product

Resources

About