Messages in this thread | | | Date | Tue, 13 Mar 2007 09:09:05 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH][RSDL-mm 0/7] RSDL cpu scheduler for 2.6.21-rc3-mm2 |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > It has been said that "perfection is the enemy of good". The two > > interactive tasks receiving 40% cpu while two niced background jobs > > receive 60% may well be perfect, but it's damn sure not good. > > Well, the real problem is really "server that works on behalf of > somebody else".
i think Mike's testcase was even simpler than that: two plain CPU hogs on nice +5 stole much more CPU time with Con's new interactivity code than they did with the current interactivity code. I'd agree with Mike that a phenomenon like that needs to be fixed.
/less/ interactivity we can do easily in the current scheduler: just remove various bits here and there. The RSDL promise is that it gives us /more/ interactivity (with 'interactivity designed in', etc.), which in Mike's testcase does not seem to be the case.
> And the problem is that a lot of clients actually end up doing *more* > in the X server than they do themselves directly.
yeah. It's a hard case because X is not always a _clear_ interactive task - still the current interactivity code handles it quite well.
but Mike's scenario wasnt even that complex. It wasnt even a hard case of X being starved by _other_ interactive tasks running on the same nice level. Mike's test-scenario was about two plain nice +5 CPU hogs starving nice +0 interactive tasks more than the current scheduler does, and this is really not an area where we want to see any regression. Con, could you work on this area a bit more?
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