We are not happy about smp implantation in qnx. The centralized OS critical section leads to very poor performances even
 if the processes are statically allocated in the cores and the software is arranged in order to minimize interference 
between the task running within the same cores.

In many cases we had better performances with mono-core software even if the hardware was multiple-core. So we developed
 a qnx hypervisor to have multiple independent instances. I would have preferred to avoid it.

I would suggest to introduce the concept of sub-os domains directly in the kernel, independent each other in terms of 
scheduling and memory management (maybe transparent to the application layer but at process creation) and a critical 
section divided in two layers. The first for the processes internal of a domain and a second one between processes 
running in different domains.