Auflistung nach Autor:in "Wulf, Christian"
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- ZeitschriftenartikelAdvanced Typing for the Kieker Instrumentation Languages(Softwaretechnik-Trends Band 36, Heft 4, 2016) Jung, Reiner; Wulf, ChristianThe observation of software systems is a complicated task due to the heterogeneity of technologies and programming languages involved. In Kieker , we address this heterogeneity with two domain-specific languages (DSLs) which allow to define event types and monitoring probes independent from specific languages. The DSLs allow to extend event types individually and to adapt probes accordingly. In monitoring, different event types are used together to observe a specific property, like call traces. In case additional attributes, like message size, must be observed, multiple types must be extended simultaneously. This is cumbersome for large sets of types and an error prone task. In case of missed types or wrongly initialized attributes, the errors may harm analysis results. We address these challenges with a new type extension mechanism and semantic constraints for attributes.
- ZeitschriftenartikelExtraction of Operational Workflow-based User Behavior Profiles for Software Modernization(Softwaretechnik-Trends Band 36, Heft 4, 2016) Dittrich Gunnar; Wulf, ChristianStatic and dynamic analysis are the core parts in the software modernization process. They are required for the architecture reconstruction and the assessment of legacy software systems. One important use case is the extraction of user behavior profiles which can help in improving the system’s frontend layer. In this paper, we present our approach to extract and to visualize operational workflow-based user behavior profiles. Its implementation is based on two Java command line tools. The first tool extracts and anonymizes sessions from the records emitted by the monitoring framework Kieker. Based on these sessions, the second tool extracts a behavior model which is stored in several different graph formats on the file system. We evaluate our tools by instrumenting an industrial workflow-based Java web application for insurers. We show that our approach is able to automatically build and visualize a corresponding hierarchical behavior model. Such a model represents business processes as parents of workflows which in turn contain the visited views. Moreover, we show that this model can help in planning and prioritizing the software modernization process by identifying the most used and the least used views as well as the common screen- and workflow.
- KonferenzbeitragIncreasing the Throughput of Pipe-and-Filter Architectures by Integrating the Task Farm Parallelization Pattern(Software Engineering 2017, 2017) Wulf, Christian; Hasselbring, WilhelmThe Pipe-and-Filter style represents a well-known family of component-based architectures. By executing each filter on a dedicated processing unit, it is also possible to leverage contemporary distributed systems and multi-core systems for a high throughput. However, this simple parallelization approach is not very effective when (1) the workload is uneven distributed over all filters and when (2) the number of available processing units exceeds the number of filters. In this paper, we explain how we utilize the task farm parallelization pattern in order to increase the throughput of Pipe-and-Filter architectures. Furthermore, we describe an associated modular self- adaptive mechanism which enables the automatic resource-efficient reaction on unevenly distributed workload. Finally, we refer to an extensive experimental evaluation of our self-adaptive task farm performed by us. The results show that our task farm (1) increases the overall throughput and (2) scales well according to the current workload.
- ZeitschriftenartikelKieker in Eclipse - A Plug-in for Application Performance Monitoring and Dynamic Analysis in Eclipse(Softwaretechnik-Trends Band 36, Heft 4, 2016) Echternkamp, Florian; Wulf, ChristianThe Kieker framework offers features to monitor and to analyse the runtime behaviour of software systems. In this paper, we propose an associated Eclipse plugin to ease the usage of Kieker for novice users and to enable the profiling in the Eclipse environment. The monitoring part of the plug-in enables the automatic integration and configuration of the monitoring via an integrated UI. In this way, an Eclipse project can be seamlessly monitored from within the Eclipse IDE. The analysis part of the plug-in provides predefined analyses and associated views for reasoning about monitored traces. It allows to sort, to filter, and to search for specific operation calls and traces. Moreover, it seamlessly integrates into Eclipse and thus enables to jump directly to the code of a selected operations call.
- KonferenzbeitragPattern-based detection and utilization of potential parallelism in software systems(Software Engineering 2014, 2014) Wulf, Christian
- ZeitschriftenartikelRadarGun: Toward a Performance Testing Framework(Softwaretechnik-Trends Band 37, Heft 3, 2017) Henning, Sören; Wulf, Christian; Hasselbring, WilhelmWe present requirements on a performance testing framework to distinguish it from a functional testing framework and a benchmarking framework. Based on these requirements, we propose such a performance testing framework for Java, called RadarGun. RadarGun can be included into a continuous integration server, such as Jenkins, so that performance tests are executed automatically during the build process. We conducted a feasibility evaluation of this approach by applying it to the continuous integration infrastructure of the Pipe-and-Filter framework TeeTime.
- ZeitschriftenartikelRefactoring Kieker’s Monitoring Component to Further Reduce the Runtime Overhead(Softwaretechnik-Trends Band 36, Heft 4, 2016) Strubel, Hannes; Wulf, ChristianKieker’s monitoring component is tuned for a low runtime overhead. Nevertheless, we recently identified potential for improvement. Unfortunately, we could utilize this potential only by refactoring major parts of its architecture. In this paper, we describe these changes and discuss their advantages. Moreover, we present an evaluation which shows that our changes reduce the runtime overhead to 17% in our setup while simultaneously having a complexity of only 73%.
- ZeitschriftenartikelSoftware Performance Anti-Patterns Observed and Resolved in Kieker(Softwaretechnik-Trends Band 35, Heft 3, 2015) Wulf, Christian; Hasselbring, WilhelmSoftware performance anti-patterns describe bad-practice solutions for particular problems. They help in sensitizing software engineering to such situations. In this paper, we focus on anti-patterns of monitoring and dynamic analysis frameworks, such as Kieker. These frameworks typically have high requirements on a low monitoring overhead and a high-throughput analysis performance. We describe three observed anti-patterns which influenced previous versions of Kieker with a high impact on the performance. Moreover, we present our solution for each of the anti-patterns.