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Improving the performance of object-oriented languages with dynamic predication of indirect jumps

acm sigplan NOTICES 2008年第3期43卷 80-90页

作者： Joao, Jose A. Mutlu, Onur Kim, Hyesoon Agarwal, Rishi Patt, Yale N. Univ Texas Austin ECE Dept Austin TX 78712 USA Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

Indirect jump instructions are used to implement increasingly-common programming constructs such as virtual function calls, switch-case statements, jump tables, and interface calls. The performance impact of indirect jumps is likely to increase because indirect jumps with multiple targets are difficult to predict even with specialized hardware. This paper proposes a new way of handling hard-to-predict indirect jumps: dynamically predicating them. The compiler (static or dynamic) identifies indirect jumps that are suitable for predication along with their control-flow merge (CFM) points. The hardware predicates the instructions between different targets of the jump and its CFM point if the jump turns out to be hard-to-predict at run time. If the jump would actually have been mispredicted, its dynamic predication eliminates a pipeline flush, thereby improving performance. Our evaluations show that Dynamic Indirect jump Predication (DIP) improves the performance of a set of object-oriented applications including the Java DaCapo benchmark suite by 37.8% compared to a commonly-used branch target buffer based predictor, while also reducing energy consumption by 24.8%. We compare DIP to three previously proposed indirect jump predictors and find that it provides the best performance and energy-efficiency.

关键词： design performance dynamic predication indirect jumps virtual functions object-oriented languages predicated execution

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Improving the performance of object-oriented languages with dynamic predication of indirect jumps

Improving the performance of object-oriented languages with ...

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13th international conference on Architectural Support for programming languages and Operating systems

作者： Joao, Jose A. Mutlu, Onur Kim, Hyesoon Agarwal, Rishi Patt, Yale N. Univ Texas Austin ECE Dept Austin TX 78712 USA Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

ISBN: (纸本)9781595939586

关键词： design performance dynamic predication indirect jumps virtual functions object-oriented languages predicated execution

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Generating Incremental Implementations of object-Set Queries 08

Generating Incremental Implementations of Object-Set Queries

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7th international conference on Generative programming and Component Engineering

作者： Rothamel, Tom Liu, Yanhong A. SUNY Stony Brook Dept Comp Sci Stony Brook NY 11790 USA

ISBN: (纸本)9781605582672

High-level query constructs help greatly improve the clarity of programs and the productivity of programmers, and are being introduced to increasingly more languages. However, the use of high-level queries in programming languages can come at a cost to program efficiency, because these queries are expensive and may be computed repeatedly on slightly changed inputs. For efficient computation in practical applications, a powerful method is needed to incrementally maintain query results with respect to updates to query parameters. This paper describes a general and powerful method for automatically generating incremental implementations of high-level queries over objects and sets in object-oriented programs, where a query may contain arbitrary set enumerators, field selectors, and additional conditions. The method can handle any update to object fields and addition and removal of set elements, and generate coordinated maintenance code and invocation mechanisms to ensure that query results are computed correctly and efficiently. Our implementation and experimental results for example queries and updates confirm the effectiveness of the method.

关键词： Automatic Incrementalization Program Optimization Query Constructs

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Sixth international workshop on SOA & web services - best practices

Sixth international workshop on SOA & web services - best pr...

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23rd acm sigplan conference on object oriented programming systems languages and Applications,OOPSLA 2008

作者： Bjerkestrand, Anders Aas Skaar, Lars Arne Lennon, Ruth Zeid, Amir Bekk Consulting AS Norway Miles Consulting AS Norway Letterkenny Institute of Technology Ireland American University of Kuwait Kuwait

Both Academia and Industry have intensified their efforts to realize the potential of Service oriented Computing and Service oriented Architecture (SOA). There are many obstacles yet to overcome in the commercial adoption, design and implementation of SOA. This workshop seeks insight from academia and industry to describe the problems encountered and formulate theoretical and propose practical solutions for their resolution from industry and academia perspectives. This workshop is a continuation of a highly successful series of workshops at OOPSLA 2007, OOPSLA 2006, OOPSLA 2005, OOPSLA 2004 and OOPSLA 2003.

关键词： Web services

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The Mapping Collector: Virtual memory support for generational, parallel, and concurrent compaction

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acm sigplan NOTICES 2008年第3期43卷 91-102页

作者： Wegiel, Michal Krintz, Chandra Univ Calif Santa Barbara Dept Comp Sci Santa Barbara CA 93106 USA

Parallel and concurrent garbage collectors are increasingly employed by managed runtime environments (MREs) to maintain scalability, as multi-core architectures and multi-threaded applications become pervasive. Moreover, state-of-the-art MREs commonly implement compaction to eliminate heap fragmentation and enable fast linear object allocation. Our empirical analysis of object demographics reveals that unreachable objects in the heap tend to form clusters large enough to be effectively managed at the granularity of virtual memory pages. Even though processes can manipulate the mapping of the virtual address space through the standard operating system (OS) interface on most platforms, extant parallel/concurrent compactors do not do so to exploit this clustering behavior and instead achieve compaction by performing, relatively expensive, object moving and pointer adjustment. We introduce the Mapping Collector (MC), which leverages virtual memory operations to reclaim and consolidate free space without moving objects and updating pointers. MC is a nearly-single-phase compactor that is simpler and more efficient than previously reported compactors that comprise two to four phases. Through effective MRE-OS coordination, MC maintains the simplicity of a non-moving collector while providing efficient parallel and concurrent compaction. We implement both stop-the-world and concurrent MC in a generational garbage collection framework within the open-source HotSpot Java Virtual Machine. Our experimental evaluation using a multiprocessor indicates that MC significantly increases throughput and scalability as well as reduces pause times, relative to state-of-the-art, parallel and concurrent compactors.

关键词： algorithms languages performance virtual memory compaction parallel concurrent

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Archipelago: Trading address space for reliability and security

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acm sigplan NOTICES 2008年第3期43卷 115-124页

作者： Lvin, Vitaliy B. Novark, Gene Berger, Emery D. Zorn, Benjamin G. Univ Massachusetts Dept Comp Sci Amherst MA 01003 USA Microsoft Res Redmond WA 98052 USA

Memory errors are a notorious source of security vulnerabilities that can lead to service interruptions, information leakage and unauthorized access. Because such errors are also difficult to debug, the absence of timely patches can leave users vulnerable to attack for long periods of time. A variety of approaches have been introduced to combat these errors, but these often incur large runtime overheads and generally abort on errors, threatening availability. This paper presents Archipelago, a runtime system that takes advantage of available address space to substantially reduce the likelihood that a memory error will affect program execution. Archipelago randomly allocates heap objects far apart in virtual address space, effectively isolating each object from buffer overflows. Archipelago also protects against dangling pointer errors by preserving the contents of freed objects after they are freed. Archipelago thus trades virtual address space-a plentiful resource on 64-bit systems-for significantly improved program reliability and security, while limiting physical memory consumption by tracking the working set of an application and compacting cold objects. We show that Archipelago allows applications to continue to run correctly in the face of thousands of memory errors. Across a suite of server applications, Archipelago's performance overhead is 6% on average (between -7% and 22%), making it especially suitable to protect servers that have known security vulnerabilities due to heap memory errors.

关键词： algorithms languages reliability security Archipelago buffer overflow dynamic memory allocation memory errors probabilistic memory safety randomized algorithms virtual memory

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Context-oriented programming in contextl: State of the art

Context-oriented programming in contextl: State of the art

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Celebrating the 50th Anniversary of Lisp, Lisp50@OOPSLA'08

作者： Costanza, Pascal Programming Technology Lab. Vrije Universiteit Brussel B-1050 Brussels Belgium

ISBN: (纸本)9781605583839

There is a wide range of scenarios where software systems have to be able to behave differently according to their context of use. In Context-oriented programming (COP), programs can be partitioned into behavioral variations that can be freely activated and combined at runtime with well-defined scopes, such that the program behavior is affected depending on context. About four years ago, we have introduced our vision of Context-oriented programming and have presented the programming language ContextL as an extension to the Common Lisp object System (CLOS), as our first language extension that explicitly realizes this vision. Since then, ContextL has been picked up by various developers world-wide, is now in use in several software systems, and has been continuously improved to meet the demands of its users. For these reasons, ContextL can currently be regarded as the most mature realization of COP concepts. In this paper, we give an overview of the major ingredients of ContextL, describe the developments in ContextL of the last four years, and sketch some future work. Copyright © 2008 acm.

关键词： Computer software

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Decentralized control of automatic guided vehicles : Applying multi-agent systems in practice

Decentralized control of automatic guided vehicles : Applyin...

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23rd acm sigplan conference on object oriented programming systems languages and Applications,OOPSLA 2008

作者： Weyns, Danny Holvoet, Tom Schelfthout, Kurt Wielemans, Jan DistriNet Labs Katholieke Universiteit Leuven Belgium Egemin International nv Belgium

An automatic guided vehicle (AGV) transportation system is a fully automated system that provides logistic services in an industrial environment such as a warehouse or a factory. Traditionally, the AGVs that execute the transportation tasks are controlled by a central server via wireless communication. In a joint effort between Egemin, an industrial manufacturer of AGV transportation systems, and DistriNet Labs research at the Katholieke Universiteit Leuven, we developed an innovative decentralized architecture for controlling AGVs. The driving motivations behind decentralizing the control of AGVs were new and future quality requirements such as flexibility and openness. At the software architectural level, the AGV control system is structured as a multi-agent system;the detailed design and implementation is object-oriented. In this paper, we report our experiences with developing the agent-based control system for AGVs. Starting from system requirements, we give an overview of the software architecture and we zoom in on a number of concrete functionalities. We reflect on our experiences and report lessons learned from applying multi-agent systems for real-world AGV control.

关键词： Automatic guided vehicles

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Automatic construction of a bug library for object-oriented novice Java programmer errors

Automatic construction of a bug library for object-oriented ...

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9th international conference on Intelligent Tutoring systems

作者： Suarez, Merlin Sison, Raymund De La Salle Univ Coll Comp Studies Manila 1004 Philippines

ISBN: (纸本)9783540691303

Machine learning techniques have been applied to the task of student modeling, more so in building tutors for acquiring programming skill. These were developed for various languages (Pascal, Prolog, Lisp, C++) and programming paradigms (procedural and declarative) but never for object-oriented programming in Java. JavaBugs builds a bug library automatically using discrepancies between a student and correct program. While other works analyze code snippets or UML diagrams to infer student knowledge of object-oriented design and programming, JavaBugs examines a complete Java program and identifies the most similar correct program to the student's solution among a collection of correct solutions and builds trees of misconceptions using similarity measures and background knowledge. Experiments show that JavaBugs can detect the most similar correct program 97% of the time, and discover and detect 61.4% of student misconceptions identified by the expert.

关键词： automatic bug library construction Java errors object-oriented programming multistrategy learning

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GC assertions: Using the garbage collector to check heap properties 08

GC assertions: Using the garbage collector to check heap pro...

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2008 acm sigplan Workshop on Memory systems Performance and Correctness, MSPC 2008, Held in Conjunction with the 13th international conference on Architectural Support for programming languages and Operating systems, ASPLOS '08

作者： Aftandilian, Edward Guyer, Samuel Z. Tufts University 161 College Ave Medford MA United States

ISBN: (纸本)9781605580494

This paper introduces GC assertions, a system interface that programmers can use to check for errors, such as data structure invariant violations, and to diagnose performance problems, such as memory leaks. GC assertions are checked by the garbage collector, which is in a unique position to gather information and answer questions about the lifetime and connectivity of objects in the heap. We introduce several kinds of GC assertions, and we describe how they are implemented in the collector. We also describe our reporting mechanism, which provides a complete path through the heap to the offending objects. We show results for one type of assertion that allows the programmer to indicate that an object should be reclaimed at the next GC. We find that using this assertion we can quickly identify a memory leak and its cause with negligible overhead. Copyright 2008 acm.

关键词： garbage collection managed languages memory leaks

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