Using OpenMP to develop multithreaded programs is very simple and easy. However, wrong execution results occur when directives are not properly used. In this paper, a correctness testing and checking technique based on onlineoffline mixed mode is proposed. Where, online correctness testing only needs to record the data relative to those parallel regions of which execution results are not correct, and at the same time, it is able to identify all wrong parallel regions through one -parse online correctness testing. Offline correctness testing needn't record relative data of parallel regions and is able to flexibly test the correctness of parallel regions modified repeatedly. The technique overcomes the shortcomings of the high overheads of the existing correctness tools which can't repeatedly test the correctness of parallel regions.
3D pre-stack Kirchhoff depth migration is one of important means for petroleum prospecting. During the imaging processing, it needs a large of ray travel time data. How to optimize the obtaining the required ray travel time data is very important to the efficiency of parallel processing the pre-stack depth migration. In this paper, in order to solve the problem of how effectively to obtain the required ray travel time, we advance one multi-level data acquisition and exchange strategy by enhancing the reusability of ray travel time. Moreover, this paper also tests the actual cases which analyze the allocated memory size, the temporary file size, as well as the various combinations of different allocated memory and temporary file size, in order to investigate the impact on the efficiency of ray travel time acquisition. The final actual test results show that the method proposed in this paper is efficient, when the number of nodes is 8, 92% performance improvement of ray travel time data acquisition may be achieved.
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