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Estimating internal memory fragmentation for java programs

JOURNAL OF SYSTEMS AND SOFTWARE 2002年第3期64卷 235-246页

作者： Skotiniotis, T Chang, JEM Iowa State Univ Dept Elect & Comp Engn Ames IA 50011 USA

Dynamic memory management has been an important part of a large class of computer programs and with the recent popularity of object oriented programming languages, more specifically java, high performance dynamic memory management algorithms continue to be of great importance. In this paper, an analysis of java programs, provided by the SPECjvm98 benchmark suite, and their behavior, as this relates to fragmentation, is performed. Based on this analysis, a new model is proposed which allows the estimation of the total internal fragmentation that java systems will incur prior to the programs execution. The proposed model can also accommodate any variation of segregated lists implementation. A comparison with a previously introduced fragmentation model is performed as well as a comparison with actual fragmentation values that were extracted from SPECjvm98. Finally the idea of a test-bed application that will use the proposed model to provide to programmers/developers the ability to know, prior to a programs execution, the fragmentation and memory utilization of their programs, is also introduced. With this application at hand developers as well as designers of applications could better assess the stability, efficiency as well reliability of their applications at compile time. (C) 2002 Elsevier Science Inc. All rights reserved.

关键词： memory fragmentation buddy system java virtual machine

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An Empirical Study of JVMs' Behaviors on Erroneous JNI Interoperations

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 2024年第4期50卷 979-994页

作者： Hwang, Sungjae Lee, Sungho Ryu, Sukyoung Sungkyunkwan Univ Dept Comp Sci & Engn Suwon 16419 South Korea Chungnam Natl Univ Dept Comp Sci & Engn Daejeon 34134 South Korea Korea Adv Inst Sci & Technol Sch Comp Daejeon 34141 South Korea

java Native Interface (JNI) allows java applications to access native libraries, but it is challenging to develop correct JNI programs. By leveraging native code, the JNI enables java developers to implement efficient applications and reuse code written in other programming languages such as C and C++. The core java libraries use the JNI to provide system features like graphical user interfaces, and mainstream java virtual machines (JVMs) support the JNI. However, implementing correct JNI programs is not trivial due to the complex interoperation semantics between different programming languages. While JVMs do not validate JNI interoperations by default because of the performance overhead, they provide two methods. First, JVMs report the interoperation failures defined in the JNI specification at runtime. Second, they support a debug option, which validates JNI interoperations, degrading the runtime performance. To the best of our knowledge, literature has not thoroughly studied the quality of JVMs' methods, even though erroneous JNI interoperations may result in incorrect behaviors. In this paper, we empirically study the behaviors of JVMs on erroneous JNI interoperations. For a systematic study, we propose JUSTGen, a semi-automatic tool that generates JNI test programs incurring erroneous interoperations from the JNI specification. JUSTGen receives the JNI specification written in our domain-specific language (DSL) and automatically discovers cases that may lead to runtime errors on interoperations using an SMT solver. It then generates test programs that trigger the behaviors on the erroneous cases. Using the generated tests, we empirically evaluate JVM's failure handling mechanisms and the debug option capabilities on erroneous JNI interoperations. Our experiment results show that there exist erroneous cases in which JVMs do not handle failures or handle them differently from the specification. We also found that the JNI debug option does not validate thousands o

关键词： java native interface java virtual machine testing empirical study debugging

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Efficient java exception handling in just-in-time compilation

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SOFTWARE-PRACTICE & EXPERIENCE 2004年第15期34卷 1463-1480页

作者： Lee, SI Yang, BS Moon, SM Seoul Natl Univ Sch Elect Engn Seoul 151742 South Korea

java uses exceptions to provide elegant error handling capabilities during program execution. However, the presence of exception handlers complicates the job of the just-in-time (JIT) compiler, while exceptions are rarely used in most programs. This paper describes two techniques for reducing such complications. First, we delay the translation of an exception handier until the exception really occurs. This on-demand translation of exception handlers allows more optimizations when translating the main flow, without being hindered by constraints caused by the exception flows. Secondly, for those exceptions that are actually thrown during program execution we insert exception-type check code and a direct branch to the translated exception handlers. This exception handler prediction is motivated by an observation that frequently thrown exceptions are likely to be handled by the same exception handlers, so this will eliminate the exception processing overhead of the java virtual machine. Our experiments indicate that the code quality of the main flow is no longer affected by the presence of exception handlers. Also, frequently thrown exceptions can be efficiently handled by the exception handier prediction. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： java virtual machine exception handling just-in-time compiler on-demand translation exception handier prediction

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A Power-Saving Technique for the OSGI Platform

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2012年第5期E95D卷 1417-1426页

作者： Chen, Kuo-Yi Lin, Chin-Yang Ma, Tien-Yan Hou, Ting-Wei Natl Cheng Kung Univ Dept Engn Sci Tainan 701 Taiwan

With more digital home appliances and network devices having OSGi as the software management platform, the power-saving capability of the OSGi platform has become a critical issue. This paper is aimed at improving the power-efficiency of the OSGi platform, i.e. reducing the energy consumption with minimum performance degradation. The key to this study is an efficient power-saving technique which exploits the runtime information already available in a java virtual machine (JVM), the base software of the OSGi platform, to best determine the timing of performing DVFS (Dynamic Voltage and Frequency Scaling). This, technically, involves a phase detection scheme that identifies the memory phase of the OSGi-enabled device/server in a correct and almost effortless way. The overhead of the power-saving procedure is thus minimized, and the system performance is well maintained. We have implemented and evaluated the proposed power-saving approach on an OSGi server, where the Apache Felix OSGi implementation and the DaCapo benchmarks were applied. The results show that this approach can achieve real power-efficiency for the OSGi platform, in which the power consumption is significantly reduced and the performance remains highly competitive, compared with the other power-saving techniques.

关键词： energy-efficient OSGi java virtual machine DVFS

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A study of page replacement performance in garbage collection heap

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JOURNAL OF SYSTEMS AND SOFTWARE 2001年第3期58卷 235-245页

作者： Lo, CTD Srisa-An, W Chang, JM IIT Dept Comp Sci Chicago IL 60616 USA

Large number of page-faults can severely degrade the performance of any system. While much attention has been paid on the virtual memory space of an entire process, the paging behavior of one particular memory segment has not been reported. Unlike the static behavior in most of the memory segments, the heap segment has unique characteristics closely related to its memory management scheme. First, this paper presents a thorough study on the effect of heap page-faults on the performance of Kaffe JVM version 1.0.5 and the Kaffe java virtual machine (JVM) with the modified buddy system. Second, a modified least recently used (mLRU) is proposed to improve the performance of the LRU page-replacement policy. Four different page-replacement policies, first-in-first-out (FIFO), Random, LRU and mLRU, are used to study the performance of each JVM. Third, the java applications used in this study are SPECjvm98 benchmark suite. These programs represent real-world workload and are highly dynamic memory intensive. Fourth, an instrumented Kaffe JVM is used to generate memory traces. Then, a simulator is used to analyze and reconstruct the heap as the benchmark programs are executed. Finally, this study has shown that the modified buddy system has less page-fault occurrences in six out of eight applications. The improvement can be up to 74%. Moreover, the proposed mLRU can improve the performance up to 68.2%. (C) 2001 Elsevier Science Inc. All rights reserved.

关键词： dynamic memory management object-oriented programming page-fault java virtual machine garbage collection system modified buddy system page replacement policy

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Active memory processor: A hardware garbage collector for real-time java embedded devices

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2003年第2期2卷 89-101页

作者： Srisa-an, W Lo, CTD Chang, JEM Univ Nebraska Lincoln NE 68588 USA Univ Texas Dept Comp Sci San Antonio TX 78249 USA Iowa State Univ Ames IA 50011 USA

java possesses many advantages for embedded system development, including fast product deployment, portability, security, and a small memory footprint. As java makes inroads into the market for embedded systems, much effort is being invested in designing real-time garbage collectors. The proposed garbage-collected memory module, a bitmap-based processor with standard DRAM cells is introduced to improve the performance and predictability of dynamic memory management functions that include allocation, reference counting, and garbage collection. As a result, memory allocation can be done in constant time and sweeping can be performed in parallel by multiple modules. Thus, constant time sweeping is also achieved regardless of heap size. This is a major departure from the software counterparts where sweeping time depends largely on the size of the heap. In addition, the proposed design also supports limited-field reference counting, which has the advantage of distributing the processing cost throughout the execution. However, this cost can be quite large and results in higher power consumption due to frequent memory accesses and the. complexity of the main processor. By doing reference counting operation in a coprocessor, the processing is done outside of the main processor. Moreover, the hardware cost of the proposed design is very modest (about 8,000 gates). Our study has shown that 3-bit reference counting can eliminate the need to invoke the garbage collector in all tested applications. Moreover, it also reduces the amount of memory usage by 77 percent.

关键词： garbage collection embedded systems real-time systems java virtual machine active memory

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A robust stack folding approach for java processors: an operand extraction-based algorithm

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JOURNAL OF SYSTEMS ARCHITECTURE 2001年第8期47卷 697-726页

作者： El-Kharashi, MW Elguibaly, F Li, KF Univ Victoria Dept Elect & Comp Engn Victoria BC V8W 3P6 Canada

Data dependency in stack operations limits the performance of java processors. To enhance java's performance, existing literature suggests using stack operations folding. We extend this concept in a new folding algorithm that identifies principle operations in folding groups and extracts necessary operands from the bytecode queue. The proposed algorithm permits nested pattern folding and multiple issue of folding groups. Hence, the need for and therefore the limitations of a stack are eliminated. This paper discusses various aspects of the proposed algorithm and illustrates different folding scenarios as well as possible hazards. Benchmarking using SPECjvm98 shows excellent performance gains as compared to existing algorithms. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： java java virtual machine java processors java performance java bytecode folding stack processors

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JGroovy: An alternative approach to implement extensible java compiler

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IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 2013年第4期8卷 380-386页

作者： Sateanpattanakul, Siwadol Hamamoto, Kazuhiko Walairacht, Aranya King Mongkuts Inst Technol Ladkrabang Fac Engn Dept Comp Engn Bangkok 10520 Thailand Tokai Univ Sch Informat & Telecommun Engn Dept Informat Media Technol Minato Ku Tokyo 1088619 Japan

The main reason for the invention of computer programming languages is for these languages to express a command-to-control machine behavior. Some of these programming languages have specific advantages that are used in specific environments such as structured query language (SQL), hypertext markup language (HTML), and spreadsheet. The common definitions of these languages are domain-specific languages (DSLs). Although DSLs are the best way to deal with specific systems, it is hard to use with other environments or platforms. Groovy is a dynamic programming language that runs on the java virtual machine. Groovy has some features that allow programmers to manage DSLs within its unique style. Groovy has some disadvantages because it does not support all java features and syntax while also producing unnecessary byte code during compilation. This paper proposes an extended-architecture technique to implement a computer programming language and compiler through extending java with Groovy language. The extensible language is called JGroovy'. And JGroovy is supported both by java and Groovy language. We implement the compiler for JGroovy and call it the JGroovy compiler' (JGC). By its extended architecture, JGC is more compatible for java source code than javac can claim to be. And it also produces a better and more compact byte code than the Groovy compiler, with an approximate improvement of 8-12%. (c) 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

关键词： programming language java language specification java virtual machine compiler construction

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Large-scale characterization of java streams

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SOFTWARE-PRACTICE & EXPERIENCE 2023年第9期53卷 1763-1792页

作者： Rosales, Eduardo Basso, Matteo Rosa, Andrea Binder, Walter Univ Svizzera Italiana Fac Informat Lugano Switzerland Univ Svizzera Italiana Fac Informat CH-6900 Lugano Switzerland

java streams are receiving the attention of developers targeting the java virtual machine (JVM) as they ease the development of data-processing logic, while also favoring code extensibility and maintainability through a concise and declarative style based on functional programming. Recent studies aim to shedding light on how java developers use streams. However, they consider only small sets of applications and mainly apply manual code inspection and static analysis techniques. As a result, the large-scale dynamic analysis of stream processing remains an open research question. In this article, we present the first large-scale empirical study on the use of streams in java code exercised via unit tests. We present stream-analyzer, a novel dynamic program analysis (DPA) that collects runtime information and key metrics, which enable a fine-grained characterization of sequential and parallel stream processing. We use a fully automatic approach to massively apply our DPA for the analysis of open-source software projects hosted on GitHub. Our findings advance the understanding of the use of java streams. Both the scale of our analysis and the profiling of dynamic information enable us to confirm with more confidence the outcome highlighted at a smaller scale by related work. Moreover, our study reports the popularity of many features of the Stream API and highlights multiple findings about runtime characteristics unique to streams, while also revealing inefficient stream processing and stream misuses. Finally, we present implications of our findings for developers of the Stream API, tool builders and researchers, and educators.

关键词： code repositories dynamic program analysis empirical studies GitHub java streams java virtual machine

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Transparently obtaining scalability for java applications on a cluster

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JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2000年第10期60卷 1159-1193页

作者： Aridor, Y Factor, M Teperman, A Eilam, T Schuster, A IBM Haifa Res Lab Ctr Adv Technol Matam IL-31905 Haifa Israel Technion Israel Inst Technol IL-32000 Haifa Israel

cJVM is a java virtual machine (JVM) which provides a single system image of a traditional JVM while executing in a distributed fashion on the nodes of a cluster. cJVM virtualizes the cluster. transparently distributing the objects and threads of any pure java application. The aim of cJVM is to obtain improved scalability Tor java server applications by distributing the application's work among the cluster's computing resources, cJVM's architecture, its unique object model, thread, and memory models, were described by Y. Aridor et al. (1999. in "International Conference on Parallel Processing, September 21-24) and at http://***/projects/systech/***. In this article, we focus on the optimization techniques employed in cJVM to achieve high scalability. In particular, we focus on the techniques used to enhance locality, thereby reducing the amount of communication generated by cJVM. Our optimization techniques are based on three principles. First, we employ a large number of mostly simple optimizations which address caching, locality of execution, and object migration. Second, we take advantage of the java semantics and of common usage patterns in implementing the optimizations. Third, we use speculative optimizations. taking advantage of the fact that the cJVM run-time environment can correct false speculations. We have demonstrated the usefulness of these techniques on a large 110 Kloc), real. java application where we demonstrate an 80% efficiency on a four-node cluster. This paper discusses the various techniques used and reports our results. (C) 2000 Academic Press.

关键词： cluster java java virtual machine distributed computing scalability high performance computing

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