Re: sched_fair: vruntime and min_vruntime will be overflow?

From: KOSAKI Motohiro
Date: Fri Mar 05 2010 - 02:20:51 EST


> hi,
>
> when enqueue or dequeue the task, the se->vruntime and cfs_rq->min_vruntime will
> increased, i want to know it is will be overflow in future time?

Let's quick calculation.

type of vruntime is u64.

1 year = 365 x 24 x 60 x 60 x 1000 x 1000 x 1000 nanosec
~= 3 x 10^16
~= 2^55
2^64 / 2^55 = 2^9 ~= 500 year.

then, 500 years after you can see overflow if you still live. :)



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