This code is mostly taken from the 1.1 port (which was in turn taken from
Dave Mills's kern.tar.Z example). A few significant differences:
1) ntp_gettime() is now a MIB variable rather than a system call. A few
fiddles are done in libc to make it behave the same.
2) mono_time does not participate in the PLL adjustments.
3) A new interface has been defined (in <machine/clock.h>) for doing
possibly machine-dependent things around the time of the clock update.
This is used in Pentium kernels to disable interrupts, set `time', and
reset the CPU cycle counter as quickly as possible to avoid jitter in
microtime(). Measurements show an apparent resolution of a bit more than
8.14usec, which is reasonable given system-call overhead.
Added "sys/rtprio.h" with the used defines.
Added rtprio(2) - the kernel interface. init_sysent.c,
kern_resource.c
syscalls.master
Added 32 new runqueues (rtqs), with initialization. kern_proc.c
kern_synch.c
Realtime processes do not change nice/priority kern_synch.c
Added a column "rt" to ddb's ps (#ifdef RTPRIO_DEBUG) kern_synch.c
Realtime priorities are enherited through fork(). kern_fork.c
Init (and children) NOT run as realtime process. init_main.c
Submitted by: Henrik Vestergaard Draboel
Bruce Evans
Andrey A. Chernov
David Greenman
Søren Schmidt
Garrett Wollman
Andreas Schulz
Poul-Henning Kamp
Doug Rabson
Rodney W. Grimes