Special schedulers, one CPU only kernel, one only userland

[John Baldwin]

On Wednesday 10 August 2005 10:10 pm, gnn at freebsd.org wrote:
> But, the question, which is interesting to me for other reasons
> (namely putting in various real-time schedulers) was not answered.  Do
> we currently have the requisite primitives to implement different
> schedulers or is there still a lot of jiggery/pokery required?

Yes, there is some room for different schedulers, but the idea of using a 
master/slave SMP system is not ust a different scheduler, but an entirely 
different SMP architecture.  That said, if you added one more sched_foo call 
for synchronous kernel entry in trap() and syscall(), you probably could 
provide a master/slave setup via a custom scheduler.  It would be more 
optimal to also tweak the low-level routing of interrupts to CPUs on 
architectures that support it as well, though that would not be required.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org