Automatic Kernel Offload Using BPF

BPF support in Linux has made kernel extensions easier. Recent efforts have shown that using BPF to offload portions of server applications, e.g., memcached and service proxies, can improve application performance and efficiency. However, thus far, the community has not looked at the question of what parts of an application should be offloaded? This paper first shows that blindly offloading application functionality to the kernel is neither beneficial nor desirable, and care must be taken when deciding what to offload. Furthermore, when deciding what to offload, developers must consider not just the application, but also the workload being handled, and the kernel being targetted, Therefore, we advocate automating this decision process in a compiler, that can analyze application code, and produce two executables, a kernel offload and a userspace program, that jointly implement the application's functionality. This paper discusses the challenges that must be addressed to build such a compiler, and why they can be feasibly addressed.