Aperfeiçoamento da biblioteca libRastro de geração de rastros de execução de programas

Abstract

Nowadays there’s a great need of processing power. It’s common the use of multi- processor machines to satisfy this need. It’s used also for this purpose to build distributed systems composed of various machines connected through a network. Multithreaded pro- grams are used to take total advantage of the multiprocessor machines capacity. The fol- lowing of the execution of programs which execute various parts at the same time isn’t an easy task. The execution trace generation is a well suited technique for multithreaded and distributed software debugging and performance analysis. The libRastro is a library and a toolkit which can be used to instrument programs to generate execution traces. These traces are useful to perform a post-mortem visualization of its behavior. In this kind of tool it’s desirable a high precision level in the events time stamp and few modification of the instrumented software’s original behavior. This paper describes the enhancement of this library’s time stamping and buffer management. Concerning to the time stamps, it’s described the implementation of a method of obtaining it which is better optimized and accurate than the original. Concerning to the buffers, it has been implemented the use of a shared buffer among the threads. To do it, an assembly instruction wich guarantees mutual exclusion in an efficient way was used.