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SubjectRe: [PATCH] sched: Initialize rq->age_stamp on processor start
On Thu, May 08, 2014 at 01:47:39PM -0500, minyard@acm.org wrote:
> From: Corey Minyard <cminyard@mvista.com>
>
> If the sched_clock time starts at a large value, the kernel will spin
> in sched_avg_update for a long time while rq->age_stamp catches up
> with rq->clock.
>
> The comment in kernel/sched/clock.c says that there is no strict promise
> that it starts at zero. So initialize rq->age_stamp when a cpu starts up
> to avoid this.
>
> I was seeing long delays on a simulator that didn't start the clock at
> zero. This might also be an issue on reboots on processors that don't
> re-initialize the timer to zero on reset, and when using kexec.
>
> Signed-off-by: Corey Minyard <cminyard@mvista.com>

Thanks
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