PacketCache: Improving OS Stacks for Streaming with Identical Contents

The streaming services with identical contents are common on the Internet. They are mainly caused by highly redundant requests. The operating system network protocol stack has some inbuilt mechanisms for transmission. However, they are still inefficient without considering the characteristic of the identical content delivery. In this paper, we propose PacketCache to optimize the network stack for the identical-content delivery. By exploiting an in-kernel cache scheme and incoming packet parsers, PacketCache can take a shortcut in the kernel and directly transmit cached contents. PacketCache also provides an enhanced mechanism called lazy upcall that defers or eliminates context switches and operations related to the virtual file systems. We evaluate PacketCache with a network file server and Nginx. The results show that PacketCache can reduce the transmission completion time by over 60% compared with the conventional kernel network stack.