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SyncChecker: Detecting Synchronization Errors between MPI Applications and Libraries
| Citations: | 2 - 0 self |
BibTeX
@MISC{Chen_syncchecker:detecting,
author = {Zhezhe Chen and Xinyu Li and Jau-yuan Chen and Hua Zhong and Feng Qin},
title = {SyncChecker: Detecting Synchronization Errors between MPI Applications and Libraries},
year = {}
}
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Abstract
Abstract—While improving the performance, nonblocking communication is prone to synchronization errors between MPI applications and the underlying MPI libraries. Such synchronization error occurs in the following way. After initiating nonblocking communication and performing overlapped computation, the MPI application reuses the message buffer before the MPI library completes the use of the same buffer, which may lead to sending out corrupted message data or reading undefined message data. This paper presents a new method called SyncChecker to detect synchronization errors in MPI nonblocking communication. To examine whether the use of message buffers is well synchronized between the MPI application and the MPI library, SyncChecker first tracks relevant memory accesses in the MPI application and corresponding message send/receive operations in the MPI library. Then it checks whether the correct execution order between the MPI application and the MPI library is enforcedbytheMPIcompletioncheckroutines.Ifnot,SyncChecker reports the error with diagnostic information. To reduce runtime overhead, we propose three dynamic optimizations. We have implemented a prototype of SyncChecker on Linux and evaluated it with seven bug cases, i.e., five introduced by the original developers and two injected, in four different MPI applications. Our experiments show that SyncChecker detects all the evaluated synchronization errors and provides helpful diagnostic information. Moreover, our experiments with seven NAS Parallel Benchmarks demonstrate that SyncChecker incurs moderate runtime overhead, 1.3-9.5 times with an average of 5.2 times, making it suitable for software testing.
Keyphrases
mpi application mpi library synchronization error detecting synchronization error message buffer moderate runtime overhead dynamic optimization new method original developer reading undefined message data correct execution order relevant memory access corrupted message data nonblocking communication different mpi application diagnostic information corresponding message na parallel benchmark runtime overhead bug case helpful diagnostic information performing overlapped computation underlying mpi library software testing following way receive operation
