Messages in this thread | | | From | Rusty Russell <> | Subject | Re: cross-cpu balancing with the new scheduler | Date | Mon, 14 Jan 2002 15:37:27 +1100 |
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In message <Pine.LNX.4.40.0201131842570.937-100000@blue1.dev.mcafeelabs.com> yo u write: > On Mon, 14 Jan 2002, Rusty Russell wrote: > > > This could be fixed by making "nr_running" closer to a "priority sum". > > I've a very simple phrase when QA is bugging me with these corner cases : > > "As Designed"
My point is: it's just a heuristic number. It currently reflects the number on the runqueue, but there's no reason it *has to* (except the name, of course).
1) The nr_running() function can use rq->active->nr_active + rq->expired->nr_active. And anyway it's only as "am I idle?".
2) The test inside schedule() can be replaced by checking the result of the sched_find_first_zero_bit() (I have a patch which does this to good effect, but for other reasons).
The other uses of nr_running are all "how long is this runqueue for rebalancing", and Ingo *already* modifies his use of this number, using the "prev_nr_running" hack.
Hope that clarifies, Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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