An integrated record&replay mechanism for nondeterministic message passing programs

Abstract

Nondeterminism is a characteristic of many parallel programs that needs dedicated support from analysis tools and programming environments. In order to allow cyclic debugging of such programs, record&replay mechanisms are used most frequently. Such techniques operate in two phases, where the record phase traces a program’s execution that can be arbitrarily repeated during subsequent replay phases. In contrast to most existing approaches, this paper describes a mechanism that is transparently integrated in the underlying message passing interface. The main advantage of this approach is its omnipresence, such that a program’s execution can be repeated immediately after it has been observed. Other benefits are the lack of instrumentation and a corresponding simplification of the whole technique for inexperienced users. The difficulties addressed by this approach are concerned with the amount of monitor overhead, which must neither perturb the program’s execution nor generate huge amounts of trace data.