In addition, we implemented this scheme in the Cilk Plus runtime system and our evaluation indicates that processor-obliviousness does not cause substantial overheads. We provide theoretical guarantees for our record and replay scheme-namely that record is optimal for programs with one lock and replay is near-optimal for all cases. In this article, we present a processor-oblivious record-and-replay scheme for dynamic multithreaded languages where record and replay can use different number of processors and both are scheduled using work stealing. Thread-based record-and-replay would violate the processor-oblivious nature of these programs, as they incorporate the number of threads into the recorded information, constraining the replayed execution to the same number of threads.

Instead, these languages provide a processor-oblivious model of programming, where programs expose task parallelism using high-level constructs such as spawn/sync without regard to the number of threads/cores available to run the program. Dynamic multithreaded languages and libraries, such as the Cilk family, OpenMP, TBB, and the like, do not have a notion of threads. Existing record-and-replay systems generally target thread-based execution models, and record the behaviors and interleavings of individual threads.

Record-and-replay systems are useful tools for debugging non-deterministic parallel programs by first recording an execution and then replaying that execution to produce the same access pattern.

Openmp program for fibonacci series