On Tuesday 01 May 2007 04:50, Andrew Morton wrote:
> On Tue, 27 Mar 2007 13:10:39 +1100
>
> Con Kolivas <[email protected]> wrote:
> > Staircase Deadline cpu scheduler policy
>
> I'll be dropping this from -mm now. I don't think we're learning anything
> more by having it in there and I generally want to get things more back
> into sync.
>
> For the record, I don't recall any problem reports arising from SD's
> presence in -mm (Except for possibly Jiri's recent "many processes end up
> in D state", but we don't have a clue what's causing that yet).
Thanks. It was a worthwhile putting it in -mm anyway because it allowed me to
shake up a lot of bugs and stabilise it. Now SD will stick around for
comparison. It also appears to me, having discussed with many people now,
that hardly anyone understands how it actually works. In summary it is an
O(1) dual array bitmap lookup based system for creating a minimal overhead
earliest eligible virtual deadline first design. I guess I never really made
that clear and now, ironically, with people quoting papers on that particular
design now I probably should have. I appreciate the code does not in any way
make it clear that that's the case because of the unique approach I used and
doesn't really do or display any calculations in the code; it is all managed
by handing out entitlements at priority intervals.
Anyway, good, bad or indifferent I intend to keep it around for comparison to
drive cfs further.
--
-ck
On Wed, 02 May 2007, Con Kolivas wrote:
> Anyway, good, bad or indifferent I intend to keep it around for comparison to
> drive cfs further.
Well, just to let you know some of us really like the design, and prefer to
use SD and have an extremely strict scheduling priority set through nice
levels, so it is not there just to drive CFS further :-) I imagine people
in the embedded world might want it for that reason, too.
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh