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Kalibera, Tomas; Hagelberg, Jeff; Pizlo, Filip; Plsek, Ales; Titzer, Ben L.; Vítek, Jan

doi:10.1145/1620405.1620412

Cited by 55 publications

(2 citation statements)

References 22 publications

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“…As an example, we consider the refinement of an action that models the behaviour of the collision detector (CD x benchmark) in [18]. The CD x SCJ program consists of a single mission that periodically carries out the following tasks: reading a set of aircraft positions from a radar device, calculating their predicted motions, and identifying the number of aircraft at risk of colliding due to their distances decreasing below a certain threshold.…”

Section: Examplementioning

confidence: 99%

“…The CD x SCJ program consists of a single mission that periodically carries out the following tasks: reading a set of aircraft positions from a radar device, calculating their predicted motions, and identifying the number of aircraft at risk of colliding due to their distances decreasing below a certain threshold. Whereas [18] provides a sequential implementation using a single handler, we have developed a parallel program by breaking down the mission design into seven handlers: (1) a cyclic input handler that reads the next radar frame; (2) a reducer handler that performs a voxel-hashing algorithm, which partitions the space; (3) four parallel detector handlers that carry out the detection work; and (4) an output handler that communicates the result.…”

Section: Examplementioning

confidence: 99%

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Refining SCJ Mission Specifications into Parallel Handler Designs

Zeyda

Cavalcanti

2013

Electron. Proc. Theor. Comput. Sci.

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Safety-Critical Java (SCJ) is a recent technology that restricts the execution and memory model of Java in such a way that applications can be statically analysed and certified for their real-time properties and safe use of memory. Our interest is in the development of comprehensive and sound techniques for the formal specification, refinement, design, and implementation of SCJ programs, using a correct-by-construction approach. As part of this work, we present here an account of laws and patterns that are of general use for the refinement of SCJ mission specifications into designs of parallel handlers used in the SCJ programming paradigm. Our notation is a combination of languages from the Circus family, supporting state-rich reactive models with the addition of class objects and real-time properties. Our work is a first step to elicit laws of programming for SCJ and fits into a refinement strategy that we have developed previously to derive SCJ programs.

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Section: Examplementioning

confidence: 99%

Section: Examplementioning

confidence: 99%

Refining SCJ Mission Specifications into Parallel Handler Designs

Zeyda

Cavalcanti

2013

Electron. Proc. Theor. Comput. Sci.

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Quantitative dynamic‐memory analysis for Java

Garbervetsky

Yovine

Braberman

et al. 2010

Concurrency and Computation

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Space-and time-predictability are hard to achieve for object-oriented languages with automated dynamicmemory management. Although there has been significant work to design APIs, such as the Real-Time Specification for Java (RTSJ), and to implement garbage collectors to enable real-time performance, quantitative space analysis is still in its infancy. This work presents the integration of a series of compiletime analysis techniques to help predicting quantitative memory usage. In particular, we focus on providing tool assistance for identifying RTSJ scoped-memory regions, their sizes, and overall memory usage. First, the tool-suite synthesizes a memory organization where regions are associated with methods. Second, it infers their sizes in parametric closed form in terms of relevant program variables. Third, it exhibits a parametric upper bound on the amount of available free memory required to execute a method. The experiments carried out with a RTSJ benchmark, a real-time aircraft collision detector, show that semiautomatic, tool-assisted generation of scoped-based code is both helpful and doable.An interesting approach to gain control on time and space is to change the memory organization model allocating objects in regions [4,5]. The Real-time Specification for Java (RTSJ) [6] supports application-level region-based memory management through ScopedMemory areas. Under suitable conditions, this environment guarantees both predictable-time operations and predictable-space occupancy at the expense of making programming more difficult. Indeed, complying with RTSJ rules complicates reusing legacy code without careful modification [7]. More importantly in practice, it forces the programmer to adopt new coding habits and to reason in a new paradigm quite different from Java. Moreover, ensuring predictability requires providing upper-bounds of region sizes.This paper presents an integration of a series of techniques and tools into a tool-suite to help developers tackling the aforementioned problems. It also explains how to use it to produce sound and predictable scope-memory managed code from conventional Java code. The tool-suite is meant to be used following the scenario depicted in Figure 1. The basic idea is to follow a two-step approach to assist programmers in generating regions. First, infer memory scopes with the aid of escape analysis [8,9]. Second, fine tune the memory layout by resorting to a region edition tool [10] and explicit program annotations.Furthermore, the tool-chain provides two unique key features, which are independent of the way objects are organized into regions. The first is the ability to produce upper bounds of region sizes as functions of program variables [11]. Such functions are used at runtime to determine the actual sizes of RTSJ memory-scopes. The second is the symbolic over-approximation of the dynamic memory footprint of a method (including its callees) [12]. This enables checking whether the method can be safely executed without running out of memory. That is, the resulting express...

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Tailor‐made JVMs for statically configured embedded systems

Stilkerich

Thomm

Wawersich

et al. 2011

Concurrency and Computation

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SUMMARY Java still is a rather exotic language in the field of real‐time and particularly embedded systems, eventhough it could provide productivity and especially safety and dependability benefits over the dominating language C. The reasons for the lack of acceptance of Java in the embedded world are the high resource consumption caused by the Java runtime environment and the lacking language features for low‐level programming. KESO is a Java Virtual Machine (JVM) that was specifically designed for statically configured resource‐constrained embedded systems. Rather than providing a fixed subset of the Java standard functionality, KESO uses the available ahead‐of‐time knowledge to generate a Java runtime that is specifically tailored towards the particular application. A key feature of KESO is its Multi‐JVM architecture, which allows the isolated cohabitation of different applications on one hardware platform. Our evaluation uses two non‐trivial real‐time applications, a control application for a quadrotor helicopter and a collision detector, to compare the cost of an application using KESO to its C counterpart. Our results show that the resource consumption of applications developed on the base of KESO is comparable to C applications, and its mechanisms for communicating among isolated components are efficient and encourage the actual utilization of spatial isolation. Copyright © 2011 John Wiley & Sons, Ltd.

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Abstract: Java is becoming a viable platform for hard real-time computing. There are production and research real-time Java VMs, as well as applications in both military and civil sector.

Cited by 55 publications

References 22 publications

Refining SCJ Mission Specifications into Parallel Handler Designs

Refining SCJ Mission Specifications into Parallel Handler Designs

Quantitative dynamic‐memory analysis for Java

Tailor‐made JVMs for statically configured embedded systems

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