From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: figo zhang <figo1802@gmail.com>
Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org
Subject: Re: sched_fair: vruntime and min_vruntime will be overflow?
Date: Fri, 5 Mar 2010 16:20:43 +0900 (JST) [thread overview]
Message-ID: <20100305161458.3A8D.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <c6ed1ac51003042312k103aafddpda82d2d64bd5f73d@mail.gmail.com>
> 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. :)
prev parent reply other threads:[~2010-03-05 7:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-05 7:12 figo zhang
2010-03-05 7:20 ` KOSAKI Motohiro [this message]
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