Lightweight kernel (LWK) operating systems (OS) in high-end supercomputing have a proven track record of excellent scalability. However, the lack of full Linux compatibility and limited availability of device drivers in LWKs have prohibited their wide-spread deployment. Multi-kernels, where an LWK is run side-by-side with Linux on many-core CPUs, have been proposed to address these shortcomings. In a multi-kernel system the LWK implements only performance critical kernel services and the rest of the OS functionality is offloaded to Linux. Access to device drivers is usually attained via offloading. Although high-performance interconnects are commonly driven from user-space, there are networks (e.g., Intel's OmniPath or Cray's Gemini) that require device driver interaction for a number of performance sensitive operations, which in turn can be adversely impacted by system call offloading.