| With the rapid development of network technology in modern society,the demand for network time service in various fields such as national defense,economy,industry,communication,electric power and so on has become increasingly strong.The number of network users has increased dramatically,which puts forward higher requirements for the response ability of NTP server.The topic of this paper combines with the development goal of the research and development of high-performance time and frequency instruments which is the key cultivation direction of the National Time Service Center during the 13 th Five-Year Plan period.The topic also combines with the demand of time users for multi-core NTP server.NTP server platform is designed and implemented based on Raspberry Pi multi-core processors and Linux environment,and quantitative test research on server response ability is carried out.This paper has certain research significance and engineering application value.The main work of this paper are as follows:(1)The main factors affecting the response ability of NTP server are analyzed,which are network data transmission speed and request processing ability.Starting from these two factors,the hardware platform of NTP server is designed and selected.Based on four-core ARM processors and Ublox NEO-M8 T GNSS receiving module,the hardware platform of NTP server is realized,which has the optional network bandwidth of 100 Mbps and 1000 Mbps,the configurable ability of the number of processor core and quantitative test ability of server response ability.(2)The software is designed based on the hardware platform.It realizes the time service function of the NTP server with four-core processors,and to configure the number of processor core by software.And the UTC time signal is read from the Ublox NEO-M8 T module and used to calibrate the local clock of the server.NTP server response ability test software based on Windows environment is designed and implemented.(3)The test environment is constructed.Based on Windows embedded NTP client software,professional NTP client software,professional TimeAcc-007 test instrument,response ability test software and Wireshark package capture software,the function test and performance test of multi-core NTP server platform are carried out.The test results show that the time service accuracy is better than 16.5 μs,and the response ability is better than 40,000 times per second.(4)Aiming at the network transmission speed and request processing ability,the server response ability test under single-core,dual-core,three-core,four-core processors and 100 Mbps and 1000 Mbps bandwidth network interfaces are carried out.The test results show that when 100 Mbps bandwidth and 1000 Mbps bandwidth network interfaces are adopted,the response ability of the server with dual-core is 67.9% and 63.1% higher than that of single-core,respectively.Compared with dual-core,three-core and four-core have little improvement under two kinds of network bandwidth.When using the same number of processor core,the 1000 Mbps bandwidth network interface have about 1.94 times higher response ability than the 100 Mbps network bandwidth. |
