i'll try another thing too: we could perhaps get rid of rq->nr_running
and only use raw_weighted_load, because now the only main remaining
property of ->nr_running is "is it zero or not".
[ ->nr_running's only other significant use is 'group_capacity', but in
reality it is only interested in whether all CPUs in the group are
busy and what the combined cpu power of that group is, and this could
be restructured to use rq->curr and cpu_power - and become independent
of nr_running. ]
[ then there are other details like load-average, but we could change
that to be weighted-cpu-load driven - that makes sense anyway: a
reniced task should have less effect on the 'system load' than a
non-reniced task. ]
that would be one less variable to maintain in the scheduler hotpath,
and it would make smpnice an effective _replacement_ for nr_running,
instead of an add-on thing that costs a bit of performance.
Ingo
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