Messages in this thread | | | Date | Sat, 31 Dec 2005 09:13:24 +0100 | From | Mike Galbraith <> | Subject | Re: [SCHED] wrong priority calc - SIMPLE test case |
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At 02:52 PM 12/30/2005 +0100, Paolo Ornati wrote: >WAS: [SCHED] Totally WRONG prority calculation with specific test-case >(since 2.6.10-bk12) >http://lkml.org/lkml/2005/12/27/114/index.html > >On Wed, 28 Dec 2005 10:26:58 +1100 >Con Kolivas <kernel@kolivas.org> wrote: > > > The issue is that the scheduler interactivity estimator is a state > machine and > > can be fooled to some degree, and a cpu intensive task that just > happens to > > sleep a little bit gets significantly better priority than one that is > fully > > cpu bound all the time. Reverting that change is not a solution because it > > can still be fooled by the same process sleeping lots for a few seconds > or so > > at startup and then changing to the cpu mostly-sleeping slightly > behaviour. > > This "fluctuating" behaviour is in my opinion worse which is why I removed > > it. > >Trying to find a "as simple as possible" test case for this problem >(that I consider a BUG in priority calculation) I've come up with this >very simple program: > >------ sched_fooler.c -------------------------------
Ingo seems to have done something in 2.6.15-rc7-rt1 which defeats your little proggy. Taking a quick peek at the rt scheduler changes, nothing poked me in the eye, but by golly, I can't get this kernel to act up, whereas 2.6.14-virgin does.
-Mike (off to stare harder rt patch)
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