Re: [patch] CFS scheduler, -v8

Ingo Molnar
2007-05-02T19:12:46Z

* William Lee Irwin III <wli@holomorphy.com> wrote:

> The coincidental aspect would be that at the time it was written, the
> formal notion of lag was not being used particularly with respect to
> priorities and load weights. [...]

(nice levels for SCHED_OTHER are 'just' an add-on concept to the core of
CFS, in fact i had two wildly different approaches that both did the
trick for users, so i fail to see the relevance of priorities to the
core concept of measuring how much a task is waiting to get on the
runqueue via the 'fair clock' ... but lets move on.)

> Things are moving in good directions on all this as far as I'm
> concerned. Moving according to Ting Yang's analysis should wrap up the
> soundness concerns about intra-queue policy I've had. OTOH load
> balancing I know much less about (not that I was ever any sort of an
> expert on single queue affairs). [...]

the whole move to ->load_weight based calculations was to make CFS
integrate better with load-balancing and to bring the smpnice
infrastructure even more into the scheduler mainstream. [ There's a
small smpnice related buglet i fixed in -v9-to-be (based on Balbir
Singh's feedback), but otherwise it behaves quite well on SMP and that's
not a big surprise: i left the load-balancer largely intact. ]

Ingo