Abstract:

The scalability of the operating system is the ability that the performance of operating system grows with the increase of the number of CPU cores. Analyzing current mature operating systems to find the performance bottleneck in multicore environments and eliminate it has become one of the research spots of modern operating systems. Through pressure experiments of search service, it's found that the scalability of 64 cores Linux server running Nginx reverse proxy is poor and the throughput of 64 cores only increases by 3 times in comparison to 1 core. The bottleneck is that all NIC interrupts and soft interrupt handling concentrate in one core of the server. Using the NIC Flow Direction mechanisms and the Linux kernel interrupt affinity, the NIC interrupt load balancing approach is achieved. The average throughput increases by 33%. NIC interrupts load balancing in multicore environments cannot guarantee the TCP connection affinity. By modifying the code of the Linux kernel, the nonaffinity problem is solved, and the throughput keeps increasing by 9%.

Key words: multi core;operating system scalability;search service;NIC interrupts balance;TCP connection affinity