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A distributed implementation of a virtual machine for java

CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2001年第3期13卷 221-244页

作者： Aridor, Y Factor, M Teperman, A IBM Haifa Res Lab Adv Technol Ctr IL-31905 Haifa Israel

The cluster virtual machine (VM) for java provides a single system image of a traditional java virtual machine (JVM) while executing in a distributed fashion on the nodes of a cluster. The cluster VM for java virtualizes the cluster, supporting any pure java application without requiring that application be tailored specifically for it. The aim of our cluster VM is to obtain improved scalability for a class of java Server Applications by distributing the application's work among the cluster's computing resources. The implementation of the cluster VM for java is based on a novel object model which distinguishes between an application's view of an object (e.g. every object is a unique data structure) and its implementation (e.g. objects may have consistent replications on different nodes). This enables us to exploit knowledge on the use of individual objects to improve performance (e.g, using object replications to increase locality of access to objects). We have already completed a prototype that runs pure java applications on a cluster of NT workstations connected by a Myrinet fast switch, The prototype provides a single system image to applications, distributing the application's threads and objects over the cluster. We used the cluster VM to run, without change, a real java Server Application containing over 10 Kloc(double dagger) for the source code and achieved high scalability for it on a cluster. We also achieved linear speedup for another application with a large number of independent threads. This paper discusses the architecture and implementation of the cluster VM. It focuses on achieving a single system image for a traditional JVM on a cluster white describing, in short, how we aim to obtain scalability. Copyright (C) 2001 John Wiley & Sons, Ltd.

关键词： cluster machine java objects java virtual machine single system image

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Identifying Processor Bottlenecks in virtual machine Based Execution of java Bytecode

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IEICE TRANSACTIONS ON ELECTRONICS 2009年第10期E92C卷 1265-1275页

作者： Rao, Pradeep Murakami, Kazuaki Inst Syst Informat Technol & Nanotechnol Fukuoka 8140001 Japan Kyushu Univ Dept Informat ISEE Fukuoka 8140001 Japan

Despite the prevalence of java workloads across a variety of processor architectures, there is very little published data on the impact of the various processor design decisions on java performance. We attribute the lack of data to the large design space resulting from the complexity of the modern superscalar processor and the additional complexities associated with executing java bytecode using a virtual machine. To address this shortcoming, we use a statistically rigorous methodology to systematically quantify the the impact of the various processor microarchitecture parameters on java execution performance. The adopted methodology enables efficient screening of significant factor effects in a large design space consisting of 35 factors (32-billion potential configurations) using merely 72 observations per benchmark application. We quantify and tabulate the significance of each of the 35 factors for 13 benchmark applications. While these tables provide various insights into java performance, they consistently highlight the performance significance of the instruction delivery mechanism, especially the instruction cache and the ITLB design parameters. Furthermore, these tables enable the architect to identify processor bottlenecks for java workloads by providing an estimate of the relative impact of various design decisions.

关键词： processor microarchitecture java virtual machine performance bottlenecks empirical models

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Asynchronous migration of execution context in java virtual machines

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FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE 2001年第2期18卷 225-233页

作者： Shudo, K Muraoka, Y Waseda Univ Sch Sci & Engn Shinjuku Ku Tokyo 1698555 Japan

The migration of the execution context has been applied to remote execution and mobile agents, and asynchronous migration can be applied to even more applications, such as load balancing. We have therefore designed a system for the migration of java threads, one that allows asynchronous and heterogeneous migration of the execution context of the running code. This paper describes an overview of the system, the problems we have faced in designing its facilities, and the results of preliminary evaluations of its performance. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： thread migration execution context asynchronous migration runtime system java virtual machine

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Securing Sensitive Data in java virtual machines 20

Securing Sensitive Data in Java Virtual Machines

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IEEE/ACIS 20th International Conference on Software Engineering Research, Management and Applications (SERA)

作者： Deng, Lin Wei, Bingyang Guo, Jin Benke, Matt Howard, Tyler Krause, Matt Patel, Aman Towson Univ Dept Comp & Informat Sci Towson MD 21252 USA Texas Christian Univ Dept Comp Sci Ft Worth TX 76129 USA Frostburg State Univ Dept Comp Sci & Informat Technol Frostburg MD 21532 USA Natl Secur Agcy Ft George G Meade MD USA

ISBN: (纸本)9781665483506

java-based applications are widely used by companies, government agencies, and financial institutions. Every day, these applications process a considerable amount of sensitive data, such as people's credit card numbers and passwords. Research has found that the java virtual machine (JVM), an essential component for executing java-based applications, stores data in memory for an unknown period of time even after the data are no longer used. This mismanagement of JVM puts all the data, sensitive or non-sensitive, in danger and raises a huge concern to all java-based applications globally. This problem has serious implications for many "secure" applications that employ java-based frameworks or libraries with a severe security risk of having sensitive data that attackers can access after the data are thought to be cleared. This paper presents a prototype of a secure java API we design through an undergraduate student research project. The API is implemented using direct Byte buffer so that sensitive data are not managed by JVM garbage collection. We also implement the API using obfuscation so that data are encrypted. Using an initial experimental evaluation, the proposed secure API can successfully protect sensitive data from being accessed by malicious users.

关键词： Cybersecurity java java virtual machine Garbage Collection

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Hosting OpenMP Programs on java virtual machines 16

Hosting OpenMP Programs on Java Virtual Machines

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16th ACM SIGPLAN International Conference on Managed Programming Languages and Runtimes (MPLR)

作者： Gaikwad, Swapnil Nisbet, Andy Lujan, Mikel Univ Manchester Manchester Lancs England

ISBN: (纸本)9781450369770

To leverage existing virtual machine infrastructures is attractive for programming language implementors because competitive runtime performance may be achieved with a reduced effort. For example, the Truffle framework has enabled Ruby (TruffleRuby), and C (Sulong) guest language implementations to be hosted on a java virtual machine (JVM). In this paper, we present Sulong-OpenMP, the first Truffle-based implementation to support parallel programs written in C/C++ and OpenMP. Our implementation adds OpenMP support to Sulong that executes LLVM Intermediate Representation (LLVM IR) for C/C++ programs on a JVM. We outline the challenges faced in supporting OpenMP execution semantics, and the current limitations of Sulong-OpenMP. The geometric mean overhead of 1 thread Sulong-OpenMP compared to sequential Sulong execution was 2.6% for the NAS Parallel Benchmark suite, at peak runtime performance. Although this paper focuses on the correctness of our implementation concerning the OpenMP memory model, we also highlight the diminishing performance gap between the native execution with clang -O2 and our Sulong-OpenMP as only 1.2x in the best case using 4 OpenMP threads.

关键词： java virtual machine OpenMP Sulong GraalVM

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STUDYING ENERGY-ORIENTED DYNAMIC OPTIMIZATIONS IN java virtual machineS

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JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS 2009年第1期18卷 103-120页

作者： Sun, Yu Zhang, Wei So Illinois Univ Dept Elect & Comp Engn Carbondale IL 62902 USA

virtual machines have been increasingly used in embedded and mobile devices. Limited processing power and energy resources become a major challenge for modern virtual machines. The traditional virtual machines running on server computers also face the similar requirement to reduce energy dissipation. To address these challenges, a number of research works have been done in the area of energy-oriented dynamic optimization in java virtual machines (JVM). Some of them focus on virtual machine directed hardware optimizations, while others exploit pure software approaches on virtual machine or compiler to reduce energy consumption. Additionally, client/server framework among multiple processors is also used to offload power-consuming tasks from low-power devices. This paper surveys the current progress of energy-oriented dynamic optimizations in JVMs.

关键词： Dynamic compiler energy dissipation java virtual machine

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Efficient Memory Management for Hardware Accelerated java virtual machines

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ACM TRANSACTIONS ON DESIGN AUTOMATION OF ELECTRONIC SYSTEMS 2009年第4期14卷 48-1-48-18页

作者： Bertels, Peter Heirman, Wim D'Hollander, Erik Stroobandt, Dirk Univ Ghent ELIS Dept B-9000 Ghent Belgium

Application-specific hardware accelerators can significantly improve a system's performance. In a java-based system, we then have to consider a hybrid architecture that consists of a java virtual machine running on a general-purpose processor connected to the hardware accelerator. In such a hybrid architecture, data communication between the accelerator and the general-purpose processor can incur a significant cost, which may even annihilate the original performance improvement of adding the accelerator. A careful layout of the data in the memory structure is therefore of major importance to maintain the acceleration performance benefits. This article addresses the reduction of the communication cost in a distributed shared memory consisting of the main memory of the processor and the accelerator's local memory, which are unified in the java heap. Since memory access times are highly nonuniform, a suitable allocation of objects in either main memory or the accelerator's local memory can significantly reduce the communication cost. We propose several techniques for finding the optimal location for each java object's data, either statically through profiling or dynamically at runtime. We show how we can reduce communication cost by up to 86% for the SPECjvm and DaCapo benchmarks. We also show that the best strategy is application dependent and also depends on the relative cost of remote versus local accesses. For a relative cost higher than 10, a self-learning dynamic approach often results in the best performance.

关键词： Algorithms Experimentation Performance Dynamic memory management java virtual machine hardware acceleration

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Yama: A scalable generational garbage collector for java in multiprocessor systems

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2006年第2期17卷 148-159页

作者： Muthukumar, RM Janakiram, D Indian Inst Technol Dept Comp Sci & Engn Distributed & Ojbect Syst Lab Madras 600036 Tamil Nadu India

The current state-of-the-art generational garbage collector pauses all the program threads when it performs young and old generation garbage collection. As the number of program threads increases, the delay due to garbage collection also increases, thus restricting the scalability of the collector. In order to improve the scalability and reduce the pause time, an on-the-fly generational garbage collector called Yama is proposed for multiprocessor systems. This uses the on-the-fly deferred reference counting in the young generation and the DLG (Doligez Leroy Gonthier) on-the-fly mark and sweep garbage collector in the old generation. We have proposed and experimented with two novel variations of the on-the-fly deferred reference counting called Chitragupt1 and Chitragupt2 in the young generation. Yama does not pause all the application threads simultaneously. An adaptive tenuring policy based on object reference count and survival rate is also proposed. Yama has been implemented in the IBM Jikes RVM (Research virtual machine). The above claims are supported with experimental results for standard benchmark programs. The results show that Yama has an extremely low pause time in both the young and the old generation. The pause time reduction results in better response times for the user programs.

关键词： garbage collection memory management java programming languages java virtual machine on-the-fly garbage collection

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The apprentice challenge

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ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS 2002年第3期24卷 193-216页

作者： Moore, JS Porter, G Univ Texas Dept Comp Sci Austin TX 78712 USA

We describe a mechanically checked proof of a property of a small system of java programs involving an unbounded number of threads and synchronization, via monitors. We adopt the output of the javac compiler as the semantics and verify the system at the bytecode level under an operational semantics for the JVM. We assume a sequentially consistent memory model and atomicity at the bytecode level. Our operational semantics is expressed in ACL2, a Lisp-based logic of recursive functions. Our proofs are checked with the ACL2 theorem prover. The proof involves reasoning about arithmetic;infinite loops;the creation and modification of instance objects in the heap, including threads;the inheritance of fields from superclasses;pointer chasing and smashing;the invocation of instance methods (and the concomitant dynamic method resolution);use of the start method on thread objects;the use of monitors to attain synchronization between threads;and consideration of all possible interleavings (at the bytecode level) over an unbounded number of threads. Readers familiar with monitor-based proofs of mutual exclusion will recognize our proof as fairly classical. The novelty here comes from (i) the complexity of the individual operations on the abstract machine;(ii) the dependencies between java threads, heap objects, and synchronization;(iii) the bytecode-level interleaving;(iv) the unbounded number of threads;(v) the presence in the heap of incompletely initialized threads and other objects;and (vi) the proof engineering permitting automatic mechanical verification of code-level theorems. We discuss these issues. The problem posed here is also put forth as a benchmark against which to measure other approaches to formally proving properties of multithreaded java programs.

关键词： languages verification java java virtual machine parallel and distributed computation mutual exclusion operational semantics theorem proving

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Estimating internal memory fragmentation for java programs

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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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