Messages in this thread |  | | Date | Wed, 22 Oct 2014 07:39:33 +0800 | From | Yuyang Du <> | Subject | Re: [RESEND PATCH 2/3 v5] sched: Rewrite per entity runnable load average tracking |
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On Tue, Oct 21, 2014 at 04:54:35PM +0200, Peter Zijlstra wrote: > > In the thread here: lkml.kernel.org/r/1409094682.29189.23.camel@j-VirtualBox > there are concerns about the error bounds of such constructs. We can > basically 'leak' nr_cpus * threshold, which is potentially a very large > number. > > Do we want to introduce the force updated to combat this?
So introduce a force update here like:
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) ... + if (force || abs(delta) > cfs_rq->tg_load_avg_contrib / 64) {
That is good. In general, I have been lacking a theory about what threshold should be concerning overhead vs. accuracy. But I think adding a force here provides us an option to better comply with the theory if we have it.
Thanks, Yuyang
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