The offline nanovisor

Abstract

Current real-time technologies for Linux require partitioning for running RTOS alongside Linux or extensive kernel patching. The offline nanovisor is a minimal real-time library OS in a lightweight hypervisor under Linux. We describe a nanovisor that executes in an offline processor. An offline processor is a processor core removed from the running operating system. The offline processor executes userspace code through the use of a hyplet. The hyplet is a nanovisor that allows the kernel to execute userspace programs without delays. Combining these two technologies offers a way to achieve hard real-time in standard Linux. We demonstrate high-speed access in various use cases using a userspace timer in frequencies up to 20 kHz, with a jitter of a few hundred nanoseconds. We performed this on a relatively slow ARM processor.