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Re: [PATCH v2 03/12] sched/fair: Change the variable to hold the number of periods to 32bit integer

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On Tue, May 03, 2016 at 05:54:29AM +0800, Yuyang Du wrote:
> In sched average update, a period is about 1ms, so a 32-bit unsigned
> integer can approximately hold a maximum of 49 (=2^32/1000/3600/24)
> days, which means it is big enough and 64-bit is needless.

This fails to explain _why_ 49 days is enough. And what the 49 days is
enough for.

What happens when a task sleeps for more than 49 days?

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[PATCH v2 00/12] sched/fair: Optimize and clean up sched averages Yuyang Du <yuyang.du@intel.com> - 2016-05-03 07:40 +0200
  [PATCH v2 03/12] sched/fair: Change the variable to hold the number of periods to 32bit integer Yuyang Du <yuyang.du@intel.com> - 2016-05-03 07:40 +0200
    Re: [PATCH v2 03/12] sched/fair: Change the variable to hold the  number of periods to 32bit integer Peter Zijlstra <peterz@infradead.org> - 2016-05-03 10:50 +0200
  [PATCH v2 09/12] sched/fair: Add introduction to the sched average metrics Yuyang Du <yuyang.du@intel.com> - 2016-05-03 07:40 +0200
  [PATCH v2 08/12] sched/fair: Remove SCHED_LOAD_SHIFT and SCHED_LOAD_SCALE Yuyang Du <yuyang.du@intel.com> - 2016-05-03 07:40 +0200
  [PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt Yuyang Du <yuyang.du@intel.com> - 2016-05-03 07:40 +0200
    Re: [PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt Peter Zijlstra <peterz@infradead.org> - 2016-05-03 11:00 +0200

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