Messages in this thread | | | Date | Fri, 1 Aug 2014 03:16:38 +0800 | From | Yuyang Du <> | Subject | Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average |
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Hi Vincent,
On Thu, Jul 31, 2014 at 11:56:13AM +0200, Vincent Guittot wrote: > > load_sum is now the average runnable time before being weighted
So when weight changes, load_avg will completely use new weight. I have some cents:
1) Task does not change weight much, so it is practically ok
2) Group entity does change weight much, and very likely back and forth, so I really think keeping the intact history will make everything more predictable/stable, prevent thrashing, etc.
3) If you do the same for cfs_rq->load.weight, then we simply abandoned blocked entities, and all states won't compute. So we then need to maintain blocked load average again, and we just can't do cfs_rq load average as a whole anymore, but must update at the granularity of an entity...
Anyway, it does not seem to me you really need to change load_sum, no? So could you please not change it?
> The sum of usage_sum of the tasks that are on a rq, is used to detect > the overload of a rq.
I think you only need usage_sum for task and rq, but not cfs_rq. Others are ok.
> Does something like the patch below to be applied of top of your patchset, seem > reasonable add-on? >
If you only add running statistics, I am all good, and indeed reasonable if you can make good use of it. I am not at all against adding anything or adding running average or unweighted anything...
Thanks, Yuyang
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