Modeling and evaluating design alternatives for an on-lineinstrumentation system: a case study

This paper demonstrates the use of a model-based evaluation approach for instrumentation systems (ISs). The overall objective of this study is to provide early feedback to tool developers regarding IS overhead and performance; such feedback helps developers make appropriate design decisions about alternative system configurations and task scheduling policies. We consider three types of system architectures: network of workstations (NOW), symmetric multiprocessors (SMP), and massively parallel processing (MPP) systems. We develop a Resource OCCupancy (ROCC) model for an on-line IS for an existing tool and parameterize it for an IBM SP-2 platform. This model is simulated to answer several “what if” questions regarding two policies to schedule instrumentation data forwarding: collect-and-forward (CF) and batch-and-forward (BF). In addition, this study investigates two alternatives for forwarding the instrumentation data: direct and binary tree forwarding for an MPP system. Simulation results indicate that the BF policy can significantly reduce the overhead and that the tree forwarding configuration exhibits desirable scalability characteristics for MPP systems. Initial measurement-based testing results indicate more than 60 percent reduction in the direct IS overhead when the BF policy was added to Paradyn parallel performance measurement tool     

Performance analysis challenges and framework for high-performance reconfigurable computing

Reconfigurable computing (RC) applications employing both microprocessors and FPGAs have potential for large speedup when compared with traditional (software) parallel applications. However, this potential is marred by the additional complexity of these dual-paradigm systems, making it difficult to identify performance bottlenecks and achieve desired performance. Performance analysis concepts and tools are well researched and widely available for traditional parallel applications but are lacking in RC, despite being of great importance due to the applications’ increased complexity. In this paper, we explore challenges and present new techniques in automated instrumentation, runtime measurement, and visualization of RC application behavior. We also present ideas for integration with conventional performance analysis tools to create a unified tool for RC applications as well as our initial framework for FPGA instrumentation and measurement. Results from a case study are provided using a prototype of this new tool.     

Sensitivity of Performance Prediction of Message Passing Programs

This paper discusses the issues related to the accuracy of performance prediction tools for message passing programs. We present the results of two sets of experiments to quantify the effect of the instrumentation overhead and variance in the accuracy of Dimemas. The results show that this performance prediction tool can be used with a high level of confidence as the effect of instrumentation overhead on the predicted performance is minimal. We also show that it is possible to carry out instrumentation runs in highly loaded multi-user environments and still be able to accurately analyze the performance of the application as if it had run alone.     

An entropy-based algorithm for data elimination in time-driven software instrumentation

While monitoring, instrumented long running parallel applications generate huge amount of instrumentation data. Processing and storing this data incurs overhead, and perturbs the execution. A technique that eliminates unnecessary instrumentation data and lowers the intrusion without loosing any performance information is valuable for tool developers. This paper presents a new algorithm for software instrumentation to measure the amount of information content of instrumentation data to be collected. The algorithm is based on entropy concept introduced in information theory, and it makes selective data collection for a time-driven software monitoring system possible.     

基于运行时代码修改的动态性能监控关键技术研究

代码插桩是程序性能监控的重要环节。动态插桩通过对可执行程序代码的运行时修改支持动态性能监控,有助于降低性能分析工具的构建代价,提高工具易用性。本文首先阐述了Dyninst动态插桩系统的概念抽象与执行机理,然后结合大规模并行程序动态插桩的需要,对DPCL并行程序动态插桩基础设施以及基于MRNet的可扩展通信结构进行了深入分析。     

A Performance Analysis Tool for PVM Parallel Programs

In this paper,we introduce the design and implementation of ParaVT,which is a visual performance analysis and parallel debugging tool.In ParaVT,we propose an automated instrumentation mechanism.Based on this mechanism,ParaVT automatically analyzes the performance bottleneck of parallel applications and provides a visual user interface to monitor and analyze the performance of parallel programs.In addition,it also supports certain extensions.     

Inclusive development: Software engineering requirements for universally accessible interactions

The notion of ‘universal access’ reflects the concept of an Information Society in which potentially anyone (i.e. any user) will interact with computing machines, at anytime and anyplace (i.e. in any context of use) and for virtually anything (i.e. for any task). Towards reaching a successful and cost effective realization of this vision, it is critical to ensure that the future interface development tools provide all the necessary instrumentation to support inclusive design, i.e. facilitate inclusive development. In the meantime, it is crucial that both tool developers and interface developers acquire awareness regarding the key development features they should pursue when investigating for the most appropriate software engineering support in addressing such a largely demanding development goal (i.e. universally accessible interactions). This paper discusses a corpus of key development requirements for building universally accessible interactions that has been consolidated from real practice, in the course of six medium-to-large scale research projects, all completed, within a 10 years timeframe.     

Platform‐independent profiling in a virtual execution environment

Virtual execution environments, such as the Java virtual machine, promote platform‐independent software development. However, when it comes to analyzing algorithm complexity and performance bottlenecks, available tools focus on platform‐specific metrics, such as the CPU time consumption on a particular system. Other drawbacks of many prevailing profiling tools are high overhead, significant measurement perturbation, as well as reduced portability of profiling tools, which are often implemented in platform‐dependent native code. This article presents a novel profiling approach, which is entirely based on program transformation techniques, in order to build a profiling data structure that provides calling‐context‐sensitive program execution statistics. We explore the use of platform‐independent profiling metrics in order to make the instrumentation entirely portable and to generate reproducible profiles. We implemented these ideas within a Java‐based profiling tool called JP. A significant novelty is that this tool achieves complete bytecode coverage by statically instrumenting the core runtime libraries and dynamically instrumenting the rest of the code. JP provides a small and flexible API to write customized profiling agents in pure Java, which are periodically activated to process the collected profiling information. Performance measurements point out that, despite the presence of dynamic instrumentation, JP causes significantly less overhead than a prevailing tool for the profiling of Java code. Copyright © 2008 John Wiley & Sons, Ltd.     

Minimal instrumentation may compromise failure diagnosis with an ecological interface

Interfaces designed according to ecological interface design (EID) display higher-order relations and properties of a work domain so that adaptive operator problem solving can be better supported under unanticipated system conditions. Previous empirical studies of EID have assumed that the raw data required to derive and communicate higher-order information would be available and reliable. The present research examines the relative advantages of an EID interface over a conventional piping-and-instrumentation diagram (PID) when instrumentation is maximally or only minimally adequate. Results show an interaction between interface and the adequacy of the instrumentation. Failure diagnosis performance with the EID interface with maximally adequate instrumentation is best overall. Performance with the EID interface drops more drastically from maximally to minimally adequate instrumentation than does performance with the PID interface, to the point where the EID interface with minimally adequate instrumentation supports nonsignificantly worse performance than does the equivalent PID interface. Actual or potential applications of this research include design of instrumentation and displays for complex industrial processes.     

Design and Prototype of a Performance Tool Interface for OpenMP

This paper proposes a performance tools interface for OpenMP, similar in spirit to the MPI profiling interface in its intent to define a clear and portable API that makes OpenMP execution events visible to runtime performance tools. We present our design using a source-level instrumentation approach based on OpenMP directive rewriting. Rules to instrument each directive and their combination are applied to generate calls to the interface consistent with directive semantics and to pass context information (e.g., source code locations) in a portable and efficient way. Our proposed OpenMP performance API further allows user functions and arbitrary code regions to be marked and performance measurement to be controlled using new OpenMP directives. To prototype the proposed OpenMP performance interface, we have developed compatible performance libraries for the Expert automatic event trace analyzer [17, 18] and the TAU performance analysis framework [13]. The directive instrumentation transformations we define are implemented in a source-to-source translation tool called OPARI. Application examples are presented for both Expert and TAU to show the OpenMP performance interface and OPARI instrumentation tool in operation. When used together with the MPI profiling interface (as the examples also demonstrate), our proposed approach provides a portable and robust solution to performance analysis of OpenMP and mixed-mode (OpenMP+MPI) applications.     

Design and Prototype of a Performance Tool Interface for OpenMP

This paper proposes a performance tools interface for OpenMP, similar in spirit to the MPI profiling interface in its intent to define a clear and portable API that makes OpenMP execution events visible to runtime performance tools. We present our design using a source-level instrumentation approach based on OpenMP directive rewriting. Rules to instrument each directive and their combination are applied to generate calls to the interface consistent with directive semantics and to pass context information (e.g., source code locations) in a portable and efficient way. Our proposed OpenMP performance API further allows user functions and arbitrary code regions to be marked and performance measurement to be controlled using new OpenMP directives. To prototype the proposed OpenMP performance interface, we have developed compatible performance libraries for the Expert automatic event trace analyzer [17, 18] and the TAU performance analysis framework [13]. The directive instrumentation transformations we define are implemented in a source-to-source translation tool called OPARI. Application examples are presented for both Expert and TAU to show the OpenMP performance interface and OPARI instrumentation tool in operation. When used together with the MPI profiling interface (as the examples also demonstrate), our proposed approach provides a portable and robust solution to performance analysis of OpenMP and mixed-mode (OpenMP+MPI) applications.     

基于超级块支配图插装的软件测试工具设计与实现*

通过超级块支配图来分析软件测试探针的合理插装位置,可有效地减少插装探针数量,降低代码插装对程序的影响。基于超级块支配图的代码插装原理,设计一种针对C语言的软件自动测试工具(SAT),介绍了该工具中词法语法分析器、静态分析器、代码插装器等主要功能模块的具体实现方案,同时对SAT的插装性能进行了分析。     

多种动态二进制代码插入框架的研究与分析

随着软件系统功能的日益强大,软件编写的代码量呈指数趋势增长,程序错误控制和程序性能优化变得越来越困难。为了在代码量增加的情况下,有效控制程序质量,改进程序性能,程序员大多采用动态二进制分析工具进行程序分析。动态二进制代码插入框架有效地简化了动态二进制工具的构建,因此准确掌握每种动态二进制代码插入框架的特征,成为准确构建不同工具的前提。本文通过对常用的五种二进制代码插入框架进行深入研究分析,总结归纳了每种框架的特点和特定情况下的适用性,为在工具构建过程中进行框架的准确有效选择提供了参考。     

一种基于POMP的OpenMP程序负载均衡分析方法

为了准确分析OpenMP程序的负载均衡问题,详细分析了在同步点之间进行测量的恰当位置,定义了性能分析单元,给出了负载不均衡程度的计算公式,并提出了一种以性能分析单元为分析对象来测量OpenMP并行程序负载平衡的方法。该方法利用Opari对OpenMP源程序自动插入POMP性能监控函数,通过在相关的性能函数中插入定时器的方式,以分析单元为基本对象来收集程序的负载情况。该方法已在一个OpenMP性能分析工具中得到了实现,能够有效地帮助用户找出程序中负载不均衡的瓶颈。     

Source-to-Source Instrumentation for the Optimization of an Automatic Reading System

Recording address traces that occur during a program execution is a significant technique for computer performance analysis. This paper describes a software method for address tracing via the instrumentation of C based languages. All program transformations are performed at the language level. This approach, which differs from the usual methods, allows portable and flexible program instrumentation. This tool has been developed to make easier the memory optimization of LIREChèques, an automatic bank check reading system. Two applications of the tool are clearly identified: (i) data cache use optimization, (ii) dynamic memory use optimization.     

SUDS: an infrastructure for creating dynamic software defect detection tools

SUDS is a powerful infrastructure for creating dynamic software defect detection tools. It contains phases for both static analysis and dynamic instrumentation allowing users to create tools that take advantage of both paradigms. The results of static analysis phases can be used to improve the quality of dynamic defect detection tools created with SUDS by focusing the instrumentation on types of defects, sources of data, or regions of code. The instrumentation engine is designed in a manner that allows users to create their own correctness models quickly but is flexible to support construction of a wide range of different tools. The effectiveness of SUDS is demonstrated by showing that it is capable of finding bugs and that performance improves when static analysis is used to eliminate unnecessary instrumentation.     

基于反射植入的面向对象程序动态分析机制

随着软件系统的日益复杂，软件开发、维护以及进化的大部分工作和主要成本集中在对现有系统的理解上。逆向工程以支持程序理解为目标，通过分析目标系统，产生系统不同形式和不同层次的抽象表示，帮助用户从多个层面和角度理解目标系统。为了开发一种实用的逆向工程工具，文中在深入分析了反射、开放编译、植入等技术的基础上，提出了一种基于反射植入的面向对象程序动态分析机制，其主要思想是通过反射植入软件触发器获取目标系统的动态信息，这些信息由信息收集机制收集整理并保存到Cau-Graph，最后从Cau-Graph抽象出符合UML标准的动态模型图。通过项目实践发现，这种机制是可行的。     

嵌入式软件内存泄露检测方法研究

动态内存分配为C/C++语言编程人员提供了极大的灵活性,但同时也带来了一个潜在的严重问题——内存泄露。与桌面系统相比,嵌入式系统处理能力弱、内存空间小、运行时间长,如果在程序运行期间发生内存泄露,将导致系统崩溃,造成不可预料的后果,因此需要在开发调试阶段尽早检测出造成内存泄露的代码。提出了一种基于动态检测技术和程序插装技术的嵌入式软件内存泄露分布式检测方法。该方法的实现思想是当程序在目标机运行时,插装代码自动截获内存操作函数,收集内存操作相关信息并把收集到的信息发送到服务器端处理,实现了嵌入式系统内存泄露的准确检测。实验结果证明,由于采用分布式技术进行信息处理,内存泄露检测效率得到了很大的提升。     

SID-GA: An evolutionary approach for improving observability and redundancy analysis in structural instrumentation design

In this paper the core of a genetic algorithm designed to define a sensor network for instrumentation design (ID) is presented. The tool has been incorporated into a decision support system (DSS) that assists the engineer during the ID process. The algorithm satisfactorily deals with non-linear mathematical models, and considers four design objectives, namely observability, cost, reliability and redundancy, exhibiting properties that were either never addressed by existing techniques or partially dealt with in the literature. Its performance was tested by carrying out the ID of an ammonia synthesis industrial plant. Results were statistically analysed. A face validity study on the fitness function’s soundness was also assessed by a chemical engineer with insight and expertise in this problem. The technique performed satisfactorily from the point of view of the expert in ID, and therefore it constitutes a significant upgrading for the DSS.     

基于模型的嵌入式系统性能分析框架

在现代嵌入式系统中,性能的重要性日益凸显.传统的基于测量的性能分析方法在运行时对性能进行测试,往往在代码实现后才考虑实施.若此时发现的问题是体系结构或设计因素造成的,修复的代价将非常昂贵.提出了一种基于形式化模型的性能分析（formal method-based performance analysis,简称FMPA)方法框架,希望在系统开发的早期,对系统设计模型进行性能分析,以便尽早发现并解决潜在的性能问题.FMPA具有统一的对外接口（UML-MARTE),基于多种形式化模型,并可对多种系统性能指标进行分析.该方法适用于基于模型的开发过程,可为实时嵌入式系统的设计开发提供多项性能指标的参考.通过介绍利用实时模型检测技术分析响应时间与吞吐量,利用概率模型检测技术分析系统可靠性,以及FMPA方法的支撑工具FMPAer的总体设计方案,说明了FMPA方法框架的可行性.