Home PURPOSE OF THE CENTER: To develop the center to address state-of-the-art research, create innovating educational programs, and support technology transfers using commercially viable results to assist the Army Research Laboratory to develop the next generation Future Combat System in the telecommunications sector that assures prevention of perceived threats, and Non Line of Sight/Beyond Line of Sight lethal support.

How to… home page

Since benchmarks drive computer science research and industry product development, which ones we use and how we evaluate them are key questions for the community. Despite complex runtime tradeoffs due to dynamic compilation and garbage collection required for Java programs, many evaluations still use methodologies developed for C, C++, and Fortran. SPEC, the dominant purveyor of benchmarks, compounded this problem by institutionalizing these methodologies for their Java benchmark suite. This paper recommends benchmarking selection and evaluation methodologies, and introduces the DaCapo benchmarks, a set of open source, client-side Java benchmarks. We demonstrate that the complex interactions of (1) architecture, (2) compiler, (3) virtual machine, (4) memory management, and (5) application require more extensive evaluation than C, C++, and Fortran which stress (4) much less, and do not require (3). We use and introduce new value, time-series, and statistical metrics for static and dynamic properties such as code complexity, code size, heap composition, and pointer mutations. No benchmark suite is definitive, but these metrics show that DaCapo improves over SPEC Java in a variety of ways, including more complex code, richer object behaviors, and more demanding memory system requirements. This paper takes a step towards improving methodologies for choosing and evaluating benchmarks to foster innovation in system design and implementation for Java and other managed languages.

/pdf/the-dacapo-benchmarks-java-benchmarking-development-and-3pc03s7g9q.pdf

The DaCapo benchmarks: java benchmarking development and analysis

A method, system and apparatus for a mobile web (210)is presented. In one embodiment, the invention is a method of operating a web application.The method includes receiving a request from a client (210). The method further includes processing the request with a web emulator. The method also includes servicing the request from available data.

Method, apparatus and system for a mobile web client

A data layout mechanism is described for allocating metadata within a storage system employing data striping. The data layout mechanism includes a number of storage devices, each of the storage devices having storage spaces allocated to store individual data stripe units associated with a number of stripes. The data layout mechanism further includes a plurality of metadata chunks allocated within the storage devices such that (1) metadata associated with at least two data stripe units of the same stripe is stored within a single metadata chunk, and (2) the metadata chunks are evenly distributed across the storage devices.

Method and system for striping data to accommodate integrity metadata

Information and Communication Technologies in Tourism

Jalapeno is a virtual machine for JavaTM servers written in the Java language. To be able to address the requirements of servers (performance and scalability in particular), Jalapeno was designed "from scratch" to be as self-sufficient as possible. Jalapeno's unique object model and memory layout allows a hardware null-pointer check as well as fast access to array elements, fields, and methods. Run-time services conventionally provided in native code are implemented primarily in Java. Java threads are multiplexed by virtual processors (implemented as operating system threads). A family of concurrent object allocators and parallel type-accurate garbage collectors is supported. Jalapeno's interoperable compilers enable quasi-preemptive thread switching and precise location of object references. Jalapeno's dynamic optimizing compiler is designed to obtain high quality code for methods that are observed to be frequently executed or computationally intensive.

The Jalapeño virtual machine

Jalapeno is a virtual machine for Java™ servers written in Java.A running Java program involves four layers of functionality: the user code, the virtual-machine, the operating system, and the hardware. By drawing the Java / non-Java boundary below the virtual machine rather than above it, Jalapeno reduces the boundary-crossing overhead and opens up more opportunities for optimization.To get Jalapeno started, a boot image of a working Jalapeno virtual machine is concocted and written to a file. Later, this file can be loaded into memory and executed. Because the boot image consists entirely of Java objects, it can be concocted by a Java program that runs in any JVM. This program uses reflection to convert the boot image into Jalapeno's object format.A special MAGIC class allows unsafe casts and direct access to the hardware. Methods of this class are recognized by Jalapeno's three compilers, which ignore their bytecodes and emit special-purpose machine code. User code will not be allowed to call MAGIC methods so Java's integrity is preserved.A small non-Java program is used to start up a boot image and as an interface to the operating system.Java's programming features — object orientation, type safety, automatic memory management — greatly facilitated development of Jalapeno. However, we also discovered some of the language's limitations.

Implementing jalapeño in Java

This paper describes the evolution of the JikesTM Research Virtual Machine project from an IBM internal research project, called Jalapeno, into an open-source project. After summarizing the original goals of the project, we discuss the motivation for releasing it as an open-source project and the activities performed to ensure the success of the project. Throughout, we highlight the unique challenges of developing and maintaining an open-source project designed specifically to support a research community.

The Jikes Research Virtual Machine project: Building an open-source research

Single superclass inheritance enables simple and efficient table-driven virtual method dispathc. However, virtual method table dispatch does not handle multiple inheritance and interfaces. This complication has led to a widespread misimpression that interface method dispatch is inherently inefficient. This paper argues that with proper implementation techniques, Java interfaces need not be a source of significant performance degradation.

http://staff.ustc.edu.cn/~bjhua/courses/compiler/2014/readings/interface.pdf

Efficient implementation of Java interfaces: Invokeinterface considered harmless

The invention provides a method for compacting transactions which have committed at a disconnected client prior to sending the transactions to the server for replaying along with an iterative process for re-calculating the combined transaction in the event that replay at the server fails.

Anthony Cocchi

Papers

The Jalapeño virtual machine

Implementing jalapeño in Java

The Jikes Research Virtual Machine project: Building an open-source research

Efficient implementation of Java interfaces: Invokeinterface considered harmless

Transaction compaction for replay of transactions from client to server