Re: [RFC PATCH 2/3] sched: Introduce Window-Assisted CPU utilization Tracking

From: Peter Zijlstra
Date: Fri Oct 28 2016 - 03:43:36 EST


On Fri, Oct 28, 2016 at 12:10:41AM -0700, Vikram Mulukutla wrote:
> +u64 walt_ktime_clock(void)
> +{
> + if (unlikely(walt_ktime_suspended))
> + return ktime_to_ns(ktime_last);
> + return ktime_get_ns();
> +}

> +static int walt_suspend(void)
> +{
> + ktime_last = ktime_get();
> + walt_ktime_suspended = true;
> + return 0;
> +}

No, ktime_get() will not be used in the scheduler. Imagine the joy if
that thing ends up being the HPET.