Zooming Into Radio Events by Bus Snooping

In this position paper, we advocate the use of bus snooping to trace radio events. Highly precise and unintrusive, the technique leads to potentially more efficient code and enables more insightful protocol analysis than conventional code instrumentation techniques

Perfrewrite -- Program Complexity Analysis via Source Code Instrumentation

ACACES 2012 summer schoolMost program profiling methods output the execution time of one specific program execution, but not its computational complexity class in terms of the big-O notation. Perfrewrite is a tool based on LLVM's Clang compiler to rewrite a program such that it tracks semantic information while the program executes and uses it to guess memory usage, communication and computational complexity. While source code instrumentation is a standard technique for profiling, using it for deriving formulas is an uncommon approach

HarvOS: Efficient code instrumentation for transiently-powered embedded sensing

We present code instrumentation strategies to allow transiently-powered embedded sensing devices efficiently checkpoint the system's state before energy is exhausted. Our solution, called HarvOS, operates at compile-time with limited developer intervention based on the control-flow graph of a program, while adapting to varying levels of remaining energy and possible program executions at run-time. In addition, the underlying design rationale allows the system to spare the energy-intensive probing of the energy buffer whenever possible. Compared to existing approaches, our evaluation indicates that HarvOS allows transiently-powered devices to complete a given workload with 68% fewer checkpoints, on average. Moreover, our performance in the number of required checkpoints rests only 19% far from that of an "oracle" that represents an ideal solution, yet unfeasible in practice, that knows exactly the last point in time when to checkpoint

Unobtrusive Software and System Health Management with R2U2 on a Parallel MIMD Coprocessor

Dynamic monitoring of software and system health of a complex cyber-physical system requires observers that continuously monitor variables of the embedded software in order to detect anomalies and reason about root causes. There exists a variety of techniques for code instrumentation, but instrumentation might change runtime behavior and could require costly software re-certification. In this paper, we present R2U2E, a novel realization of our real-time, Realizable, Responsive, and Unobtrusive Unit (R2U2). The R2U2E observers are executed in parallel on a dedicated 16-core EPIPHANY co-processor, thereby avoiding additional computational overhead to the system under observation. A DMA-based shared memory access architecture allows R2U2E to operate without any code instrumentation or program interference

Adding traceability to an educational IDE : a thesis presented in partial fulfilment of the requirements for the Master degree in Computer Science at Massey University, Manawatu, New Zealand

High dropout and failure rate in introductory programming courses indicate the need to improve programming comprehension of novice learners. Some of educational tools have successfully used game environments to motivate students. Our approach is based on a novel type of notional machine which can facilitate programming comprehension in the context of turn-based games. The first aim of this project is to design a layered notional machine that is reversible. This type of notional machine provides bi-directional traceability and supports multiple layers of abstraction. The second aim of this project is to explore the feasibility and in particular to evaluate the performance of using the traceability in a web-based environment. To achieve these aims, we implement this type of notional machine through instrumentation and investigate the capture of the entire execution state of a program. However, capturing the entire execution state produces a large amount of tracing data that raises scalability issues. Therefore, several encoding and compression methods are proposed to minimise the server work-load. A proof-of-concept implementation which based on the SoGaCo educational web IDE is presented. The evaluation of the educational benefits and end user studies are outside the scope of this thesis

An LLVM Instrumentation Plug-in for Score-P

Reducing application runtime, scaling parallel applications to higher numbers of processes/threads, and porting applications to new hardware architectures are tasks necessary in the software development process. Therefore, developers have to investigate and understand application runtime behavior. Tools such as monitoring infrastructures that capture performance relevant data during application execution assist in this task. The measured data forms the basis for identifying bottlenecks and optimizing the code. Monitoring infrastructures need mechanisms to record application activities in order to conduct measurements. Automatic instrumentation of the source code is the preferred method in most application scenarios. We introduce a plug-in for the LLVM infrastructure that enables automatic source code instrumentation at compile-time. In contrast to available instrumentation mechanisms in LLVM/Clang, our plug-in can selectively include/exclude individual application functions. This enables developers to fine-tune the measurement to the required level of detail while avoiding large runtime overheads due to excessive instrumentation.Comment: 8 page

07341 Abstracts Collection -- Code Instrumentation and Modeling for Parallel Performance Analysis

From 20th to 24th August 2007, the Dagstuhl Seminar 07341 ``Code Instrumentation and Modeling for Parallel Performance Analysis\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available