User space scheduling, 2nd try

[Kevin Elphinstone]

rkaiser at sysgo.de wrote:

Hi Robert,


> . or am I really on uncharted ground here?

No not completely, if you can live with hierarchical proportional share
scheduling, see

Checkout Ford et al. "CPU inheritance scheduling", OSDI 96
http://www.cs.utah.edu/flux/papers/index.html

and for a look at L4 in particular

http://www.cse.unsw.edu.au/~disy/papers/index.html#ug-theses

Simon Winwood
Flexible scheduling mechanisms in L4, BE Thesis, SCS&E, UNSW, November 2000.

Have a look at Dresden as well for a more real-time slant on scheduling in L4.
I believe they use multi-level round robin and a variation on priority
inheritance (helping). I can't convey the exact details of priority assignment
etc, so your better off having a look yourself.

http://os.inf.tu-dresden.de/

I believe Jochen envisaged something "better" than proportional share, but
still keeping the flexibility, decomposability, and preserving performance.
However, this never got beyond being a vision except for the existence of
preempters (time slice + total quanta ideas) in V4, which is unfinished work.

	- Kevin