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Feedback-directed specialization of code

COMPUTER LANGUAGES SYSTEMS & STRUCTURES 2010年第1期36卷 2-15页

作者： Khan, Minhaj Ahmad Bahauddin Zakariya Univ Multan Pakistan

Based on feedback information, a large number of optimizations can be performed by the compiler. This information actually indicates the changing behavior of the applications and can be used to specialize code accordingly. code specialization is a way to facilitate the compiler to perform optimizations by providing the information regarding variables in the code. It is however difficult to select the variables which maximize the benefit of specialization. Also the overhead of specialization and code size increase are the main issues while specializing code. This paper suggests a novel method for improving the performance using specialization based on feedback information and analysis. The code is iteratively specialized after selecting candidate variables by using a heuristic, followed by generation of optimized templates. These templates require a limited set of instructions to be specialized at runtime and are valid for a large number of values. The overhead of runtime specialization is further minimized through optimal software cache of template clones whose instantiation can be performed at static compile time. The experiments have been performed on Itanium-II(IA-64) and Pentium-IV processors using icc and gcc compilers. A significant improvement in terms of execution speed and reduction of code size has been achieved for SPEc and FFTw benchmarks. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Programming languages Optimizations Specialization Compilers dynamic code generation

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Harpy: Run-time code generation in Haskell

Harpy: Run-time Code Generation in Haskell

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11th ACM SIGPLAN Haskell Workshop

作者： Grabmueller, Martin Kleeblatt, Dirk Tech Univ Berlin D-1000 Berlin Germany

We present Harpy, a Haskell library for run-time code generation of x86 machine code. Harpy provides efficient generation of machine code, a convenient domain specific language for generating code and a collection of ... 详细信息

ISBN: (纸本)9781595936745

关键词： Haskell dynamic code generation

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Flexible Cross-Domain Event Delivery for Quality-Managed Multimedia Applications

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ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 2005年第3期1卷 248-268页

作者： Poellabauer, Christian Schwan, Karsten Univ Notre Dame Dept Comp Sci & Engn Notre Dame IN 46556 USA Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

To meet end users' quality-of-service (QoS) requirements, online quality management for multimedia applications must include appropriate allocation of the underlying computing platform's resources. Previous work has developed novel operating system (OS) functionality for dynamic QoS management, including multimedia or real-time CPU schedulers and OS extensions for online performance monitoring and for adaptations, as well as QoS-aware applications that adapt their behavior to gain additional benefits from such functionality. This article describes a general OS mechanism that may be used to implement a wide variety of online quality management functions. ECalls is a communication mechanism that implements multiple cross-domain calling conventions that can be customized to the quality management needs of applications. The ECalls mechanism is based on the notions of events, event channels, and event handlers. Using events, applications can share relevant QoS attributes with OS services, and OS-level resource management services can efficiently provide monitoring data to target applications or application managers. dynamically generated event handlers can be used to customize event delivery to meet diverse application needs, for example, to achieve high scalability for Web servers or small jitter for real-time data delivery.

关键词： Design Performance Event delivery operating system quality-of-service real-time events quality management dynamic code generation

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Efficient mediators with closures for handling dynamic interfaces in an imperative language

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INFORMATION AND SOFTWARE TECHNOLOGY 2004年第5期46卷 351-357页

作者： Shinjo, Y Kubo, T Pu, C Univ Tsukuba Inst Informat Sci & Elect Tsukuba Ibaraki 3058573 Japan Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

Mediators are well-known software components in the construction of distributed systems and applications, with clear advantages when adding functionality to legacy code. However, mediators that must handle dynamic interfaces (i.e. those that may change at run-time such as callback functions) are not easy to build in most imperative languages such as C, due to the many variants implied by the dynamic interfaces. We call this kind of mediators intermediators. We propose a systematic implementation method based on the concept of closures to implement intermediators using the Tempo run-time specializer for C programs. To illustrate this method, we implemented a unified user authentication intermediator for Unix and Windows 2000 called GINA-IM. GINA-IM gets the password entries from a Unix NIS server and performs user authentication based on the Graphical Identification and Authentication (GINA) model of Windows 2000. The code of GINA-IM is a quarter of the code size of a conventional component written without our tools. GINA-IM is in production use at authors' university by two thousands of freshmen in class and several thousands of students daily. (C) 2003 Elsevier B.V. All rights reserved.

关键词： mediators intermediators run-time specialization dynamic code generation user authentication closures

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Morphable messaging: Efficient support for evolution in distributed applications

Morphable messaging: Efficient support for evolution in dist...

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2nd International Workshop on Challenges of Large Applications in Distributed Environments (CLADE 2004)

作者： Agarwala, S Eisenhauer, G Schwan, K Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

ISBN: (纸本)0769521150

All but the most briefly used systems must evolve as their mission and roles change over time. Evolution in the context of large distributed systems is extraordinarily complex because of the difficulty of upgrading all components simultaneously, and the fact that such systems are often very sensitive to changes in the message formats that underlay their communication. Prior approaches to the Problem of implementing changes in a deployed system have relied upon adhoc solutions or protocol negotiation to avoid message format mismatches. In this paper we present a novel approach that combines message meta-data and dynamic code generation to create a robust messaging system that naturally supports application evolution.

关键词： message evolution interoperability distributed systems dynamic code generation transformation PBIO

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Efficient mediators with closures for handling dynamic interfaces in an imperative language

Efficient mediators with closures for handling dynamic inter...

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18th ACM Symposium on Applied Computing

作者： Shinjo, Y Kubo, T Pu, C Univ Tsukuba Inst Informat Sci & Elect Tsukuba Ibaraki 3058573 Japan Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

关键词： mediators intermediators run-time specialization dynamic code generation user authentication closures

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Continuous program optimization: A case study

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ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS 2003年第4期25卷 500-548页

作者： Kistler, T Franz, M Univ Calif Irvine Dept Informat & Comp Sci Irvine CA 92697 USA

Much of the software in everyday operation is not making optimal use of the hardware on which it actually runs. Among the reasons for this discrepancy are hardware/software mismatches, modularization overheads introduced by software engineering considerations, and the inability of systems to adapt to users' behaviors. A solution to these problems is to delay code generation until load time. This is the earliest point at which a piece of software can be fine-tuned to the actual capabilities of the hardware on which it is about to be executed, and also the earliest point at wich modularization overheads can be overcome by global optimization. A still better match between software and hardware can be achieved by replacing the already executing software at regular intervals by new versions constructed on-the-fly using a background code re-optimizer. This not only enables the use of live profiling data to guide optimization decisions, but also facilitates adaptation to changing usage patterns and the late addition of dynamic link libraries. This paper presents a system that provides code generation at load-time and continuous program optimization at run-time. First, the architecture of the system is presented. Then, two optimization techniques are discussed that were developed specifically in the context of continuous optimization. The first of these optimizations continually adjusts the storage layouts of dynamic data structures to maximize data cache locality, while the second performs profile-driven instruction re-scheduling to increase instruction-level parallelism. These two optimizations have very different cost/benefit ratios, presented in a series of benchmarks. The paper concludes with an outlook to future research directions and an enumeration of some remaining research problems. The empirical results presented in this paper make a case in favor of continuous optimization, but indicate that it needs to be applied judiciously. In many situations, the costs of dy

关键词： design languages performance dynamic code generation continuous program optimization dynamic reoptimization

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Templates-based portable just-in-time compiler

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ACM SIGPLAN NOTICES 2003年第8期38卷 37-43页

作者： Iliasov, A Ale Lliasov Bishkek Kyrgyzstan

Usage of the platform-neutral bytecode interpreters is often limited by their restricted performance. Just-in-time compilers effectively solve this problem. However they are hard to develop and retarget. This paper demonstrates that dynamic code generation from the templates created by a C compiler can be used to build a simple and highly-portable JIT compiler.

关键词： just-in-time compilation bytecode interpretation templates dynamic code generation code inlining

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'C and tcc: A language and compiler for dynamic code generation

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ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS 1999年第2期21卷 324-369页

作者： Poletto, M Hsieh, WC Engler, DR Kaashoek, MF MIT Comp Sci Lab Cambridge MA 02139 USA Univ Utah Salt Lake City UT 84112 USA

dynamic code generation allows programmers to use run-time information in order to achieve performance and expressiveness superior to those of static code. The 'C (Tick C) language is a superset of ANSI C that supports efficient and high-level use of dynamic code generation. LC provides dynamic code generation at the level of C expressions and statements and supports the composition of dynamic code at run time. These features enable programmers to add dynamic code generation to existing C code incrementally and to write important applications (such as "just-in-time" compilers) easily. The article presents many examples of how 'C can be used to solve practical problems. The tee compiler is an efficient, portable, and freely available implementation of 'C. tee allows programmers to trade dynamic compilation speed for dynamic code quality: in some applications, it is most important to generate code quickly, while in others code quality matters more than compilation speed. The overhead of dynamic compilation Is on the order of 100 to 600 cycles per generated instruction, depending on the level of dynamic optimization. Measurements show that the use of dynamic code generation can improve performance by almost an order of magnitude;two- to four-fold speedups are common. In most cases, the overhead of dynamic compilation is recovered in under 100 uses of the dynamic code;sometimes it can be recovered within one use.

关键词： algorithms languages performance ANSI C compilers dynamic code generation dynamic code optimization

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ASHs: Application-specific handlers for high-performance messaging

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IEEE-ACM TRANSACTIONS ON NETWORKING 1997年第4期5卷 460-474页

作者： Wallach, DA Engler, DR Kaashoek, MF MIT COMP SCI LAB CAMBRIDGE MA 02139 USA

Application-specific safe message handlers (ASHs) are designed to provide applications with hardware-level network performance, ASHs are user-written code fragments that safely and efficiently execute in the kernel in response to message arrival. ASHs can direct message transfers (thereby eliminating copies) and send messages (thereby reducing send-response latency), In addition, the ASH system provides support for dynamic integrated layer processing (thereby eliminating duplicate message traversals) and dynamic protocol composition (thereby supporting modularity), ASHs offer this high degree of flexibility while still providing network performance as good as, or (if they exploit application-specific knowledge) even better than, hard-wired in-kernel implementations. A combination of user-level microbenchmarks and end-to-end system measurements using TCP demonstrates the benefits of the ASH system.

关键词： computer networks dynamic code generation modular computer systems protocols operating systems software protection user-level networking

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