A question on Unix/Ultrix CPU scheduling

[Sandeep Nijhawan]

I 've been doing some work with the Ultrix (V2.0-1) cpu scheduling
algorithms and have the following question(s) -

	If the Super User were to increase the priority of a process by
using /etc/renice to the maximum possible (-20) and then run a program
with an infinite loop (completely cpu-bound), would any other user
process on the system get the cpu at all until the priority of the super
user's process went below PUSER ? Why?

	I modified setpri() in kern_synch.c so that a process with a
certain uid would always be given a priority of (PUSER - 1) irrespective
of its p_cpu value. After I rebuilt the kernel and ran an infinte-loop
process with that uid, I could still run other processes with other uids
though they ran much less frequently. Any ideas about what's going on?

	Any help would be much appreciated. Yes, I have Bach.

Sandeep

[I am sorry if this got posted twice]