Messages in this thread | | | Date | Mon, 06 May 2013 23:00:47 +0800 | From | Alex Shi <> | Subject | Re: [PATCH v5 5/7] sched: compute runnable load avg in cpu_load and cpu_avg_load_per_task |
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> > blocked_load_avg is the expected "to wake" contribution from tasks > already assigned to this rq. > > e.g. this could be: > load = this_rq->cfs.runnable_load_avg + this_rq->cfs.blocked_load_avg;
Current load balance doesn't consider slept task's load which is represented by blocked_load_avg. And the slept task is not on_rq, so consider it in load balance is a little strange.
But your concern is worth to try. I will change the patchset and give the testing results.
> > Although, in general I have a major concern with the current implementation: > > The entire reason for stability with the bottom up averages is that > when load migrates between cpus we are able to migrate it between the > tracked sums. > > Stuffing observed averages of these into the load_idxs loses that > mobility; we will have to stall (as we do today for idx > 0) before we > can recognize that a cpu's load has truly left it; this is a very > similar problem to the need to stably track this for group shares > computation. > > To that end, I would rather see the load_idx disappear completely: > (a) We can calculate the imbalance purely from delta (runnable_avg + > blocked_avg) > (b) It eliminates a bad tunable.
I also show the similar concern of load_idx months ago. seems overlooked. :) > >> - return cpu_rq(cpu)->load.weight; >> + return (unsigned long)cpu_rq(cpu)->cfs.runnable_load_avg; > > Isn't this going to truncate on the 32-bit case?
I guess not, the old load.weight is unsigned long, and runnable_load_avg is smaller than the load.weight. so it should be fine.
btw, according to above reason, guess move runnable_load_avg to 'unsigned long' type is ok, do you think so? >
-- Thanks Alex
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