) M. Livny, R. Ramakrishnan, K. Beyer, G. Chen, D. Donjerkovic, S. Lawande, J. Myllymaki and K. Wenger Department of Computer Sciences, University of Wisconsin--Madison 1210 W. Dayton St., Madison, Wisconsin 53706 Tel: (608)262-6611, Fax: (608)262-9777 fmiron,raghu,beyer,guangshu,donjerko,ssl,jussi,wengerg@cs.wisc.edu Abstract DEVise is a data exploration system that allows users to easily develop, browse, and share visual presentations of large tabular datasets (possibly containing or referencing multimedia objects) from several sources. The DEVise framework, implemented in a tool that has been already successfully applied to a variety of real applications by a number of user groups, makes several contributions. In particular, it combines support for extended relational queries with powerful data visualization features. Datasets much larger than available main memory can be handled---DEVise is currently being used to visualize datasets well in excess of 100MB--- and data can be in...

Interactive program steering permits researchers to monitor and guide their applications during runtime. Interactive steering can help make end users more effective in addressing the scientific or engineering questions being solved with these programs, and it may be used to improve the performance of complex parallel and distributed codes. Progress is a toolkit for developing steerable applications. Users instrument their applications with library calls and then steer parallel applications with Progress' runtime system. Progress provides steerable objects which encapsulate program abstractions for monitoring and steering during program execution. Once created, steering objects are known to and manipulated by Progress' two components: (1) a server executing in the same memory space as the target program and capable of inspecting and manipulating program state, and (2) a potentially remote client providing command and graphical interfaces. Developers instrument their applications with t...

Performance assertion checking is an approach to describing and monitoring the performance of complex software systems. The idea is simple: system implementors write assertions that capture their expectations for performance, the system is instrumented to collect performance data, and then the assertions are checked automatically against the data to detect violations signifying potential performance bugs. Because performance assertions provide a means of filtering data based on expectations, they form a good basis for tools. Data indicating that a system is performing as expected can be discarded automatically, while data indicating potential problems can be brought to the attention of a person.

An important step toward efficient software maintenance is to locate the code relevant to a particular feature. In this paper we report a study applying an execution slice-based technique to a reliability and performance evaluator to identify the code which is unique to a feature, or is common to a group of features. Supported by tools called ATAC and Vue, the program features in the source code can be tracked down to files, functions, lines of code, decisions, and then c- or p-uses. Our study suggests that the technique can provide software programmers and maintainers with a good starting point for quick program understanding.

There is a constant need for practical, efficient and costeffective software evolution techniques. We propose a novel evolution methodology that integrates the concepts of features and component-based software engineering (CBSE). We collect information about a legacy system's features through interviews with key developers, users of the system and analyzing the existing regression test cases. We found that regression test cases are untapped resources, as far as information about system features is concerned.

this paper are chosen from actual measurements made on the UNIX kernel running the Ficus operating system, 16,17 which is a modified version of SunOS 4.1.1, on a Sparcstation IPC. Since kitrace is designed for kernel development, its use presupposes familiarity with the code being measured. For those readers unfamiliar with the aspects of the UNIX kernel used in our examples, a brief summary is in order

Current software visualization tools are inadequate for understanding, debugging, and tuning realistically complex applications. These tools often present only static structure, or they present dynamics from only a few of the many layers of a program and its underlying system. This paper introduces "PV", a prototype program visualization system which provides concurrent visual presentation of behavior from all layers, including: the program itself, user-level libraries, the operating system, and the hardware, as this behavior unfolds over time. PV juxtaposes views from different layers in order to facilitate visual correlation, and allows these views to be navigated in a coordinated fashion. This results in an extremely powerful mechanism for exploring application behavior. Experience is presented from actual use of PV in production settings with programmers facing real deadlines and serious performance problems.

Traces of program executions are a helpful source of information for automated debugging. They, however, usually give a too low level picture of the executed program. Opium, our extendable trace analyser for Prolog, is connected to a "standard" tracer. Opium is programmable and extendable. It provides a trace query language and abstract views of executions which solve the problems of low-level traces. Opium has shown its capabilities to build abstract tracers and automated debugging facilities. This article describes the trace query mechanism, from the model to its implementation. Characteristic examples are detailed. Extensions written so far on top of the trace query mechanism are listed. Two recent extensions are presented: the abstract tracers for the LO (Linear Objects) and the CHR (Constraint Handling Rules) languages. These two extensions were specied and implemented within a few days. They show how to use Opium for real applications.

Programming non-sequential computer systems is hard! Many tools and environments have been designed and implemented to ease the use and programming of such systems. The majority of the analysis tools is event-based and uses event traces for representing the dynamic behavior of the system under investigation, the object system. Most tools can only be used for one special object system, or a specific class of systems such as distributed shared memory machines. This limitation is not obvious because all tools provide the same basic functionality. This article discusses approaches to implementing object-independent event trace monitoring and analysis systems. The term object-independent means that the system can be used for the analysis of arbitrary (non-sequential) computer systems, operating systems, programming languages and applications. Three main topics are addressed: objectindependent monitoring, standardization of event trace formats and access interfaces and the application-indepe...

As programs evolve, their code increasingly becomes tangled by programmers and requirements. This mosaic quality complicates program comprehension and maintenance. Many of these activities can benefit from viewing the program as a collection of features. We introduce an inexpensive and easily comprehensible summary of program changes called the feature signature and investigate its properties. We find a remarkable similarity in the nature of feature signatures across multiple non-trivial programs, developers and magnitudes of changes. This indicates that feature signatures are a meaningful notion worth studying. We then show numerous applications of feature signatures, establishing their utility. 1