Abstract: Network traffic detection is the most basic and important part of network measurement.The detection method based on Sketch can count data flow of network,which can distinguish elephant flow,detect and locate abnormal traffic in abnormal detection of network traffic.Higher requirement of the memory resources is needed for multiple hash functions used in the implementation of Sketch.To address the restriction problems raised by multiple hash functions applied in the realization of Sketch,a me-thod of improving the performance of Sketch algorithm using AVX instruction set is put forward,and also the effects on CPU instruction consumption and algorithm computing efficiency are studied,which had high efficiency and high maturity.Firstly,the elements of data stream are described and stored in the form of a vector,utilizing AVX instructions to realize structures and opera-tions of vectors.Secondly,multiple hash operations are transformed into a vector operation,which reduces the CPU resources consumption of the Sketch algorithm,improves the comprehensive performance of multiple hash functions,and made it possible to improve the optimized performance of Sketch algorithm.Finally,AVX instruction set is used to optimize the key functions in the Count-Min Sketch algorithm program,and the optimized code is tested and analyzed.The experimental results show that the AVX optimized version takes 25% time of the original version in the operation of hash function.When the data length is short,the instructions consumed by multiple hash functions are relatively small in the whole Sketch,and the AVX optimized version consumes about 70% time of the original version.As the length of the data increases,instructions consumed by multiple hash functions take up a larger proportion in the whole Sketch algorithm,and the time consumed by the AVX optimized version can be reduced to 40% of the original version.The simulation results demonstrate the effectiveness of the proposed algorithm in improving the measurement efficiency of network data flow.

Key words: AVX instruction set, CPU speed, Network measurement, Sketch