Most people consider unikernels to be single process without threads. IncludeOS is rather liberal and has rudimentary multicore support. There is no preemption

Most people consider unikernels to be single process without threads. IncludeOS is rather liberal and has rudimentary multicore support. There is no preemption however so the "threads" will have to yield if there are more threads than cores. So more like fibers than threads, really. The hypervisor typically doesn't care. So if you are using multiple cores in your application it will schedule and de-schedule your VM as per the regular rules. IncludeOS is capable of booting on bare metal and we have some basic SMP tests passing. This is currently mostly of academic interest but if you don't mind having no pre-emption you can, once we improve our hardware support, have an application that runs on multiple physical cores. Perhaps this might be of interest to people with very strict latency requirements.