Research On Fine-grained Estimation Method Of COStream Dataflow Program Workload

With the rapid development of Internet technology,single-core processors can no longer meet the needs of large-scale data calculations,and multi-core parallel computing has become an important method to increase the calculation rate.Dataflow programming is a programming model for large-scale intensive computing and multi-core computing.It implements parallel computing by dividing computing tasks into subtasks and assigning them to different cores.The premise of task division is to estimate the workload of the task.The accuracy of the estimation affects the effect of task division,and then affects the parallelism of computing tasks.Aiming at the current lack of fine-grained workload estimation methods,a workload estimation method based on program statements is designed and implemented.This method is based on the basic calculation of the test program statement and the number of clock cycles required for the operation,classifies the structure and calculation type of the program,and analyzes and judges the path of program execution by means of the constant propagation mechanism in the compiler,and is aimed at different program structures.Different workload estimation methods is used to finely calculate the number of clock cycles required for program execution.As the compiler optimizes the source code during the compilation period,changes the actual execution of the program statement,resulting in a certain error in the estimated workload according to the source program statement.In order to reduce this error,the estimation method of the workload is adjusted according to the compilation optimization processing,so that the workload estimation is based on the actual execution.The program statement further improves the accuracy of workload estimation.In view of the inaccuracy of the original COStream workload estimation method,the fine-grained workload estimation method is applied to the COStream compiler to improve the performance of the COStream compiler.The X86 structure multi-core processor is used as the experimental platform,and test cases covering each program structure type are selected to test the accuracy of the finegrained workload estimation method.The test results show that the estimation method has high accuracy.Select the most widely used algorithms in the digital media field,and test the COStream compiler after applying the fine-grained workload estimation method.The test results show that COStream has improved the speedup of the program.At the same time,the error between the theoretical value and the actual value of the speedup ratio calculated by the compiler is smaller.