Scheduler Question

[Garrett Cooper]

On Sat, Oct 9, 2010 at 4:46 PM, Eknath Venkataramani
<eknath.iyer at gmail.com> wrote:
> D&I of the FreeBSD Operating System says it's gonna refer to the BSD default
> scheduler, the 'time share scheduler' does this mean sched_4BSD.c(In the
> introduction section of Chapter 4) handles only time-share process?
> If so, then how (or where) are the kernel processes/real time process
> scheduled?

    The Design and Implementation of the FreeBSD Operating System is
unfortunately extremely out of date (my edition which I think is the
latest one refers to FreeBSD 5.2). The FreeBSD scheduler was switched
over to sched_ule.c as the default scheduler in 7.1.
    So I'd invest more time in determining how SCHED_ULE works rather
than SCHED_4BSD going forward (even though learning about SCHED_4BSD
is a good lesson in history of design of FreeBSD).
    FWIW the algorithm of prioritization, quantization of time slices,
etc for SCHED_4BSD are discussed more in depth in the chapter.
Cheers,
-Garrett