Re: [RFT][PATCH v2 2/3] cpuidle: teo: Skip tick_nohz_get_sleep_length() call in some cases

Anna-Maria Behnsen
2023-08-11T08:52:15Z

Hi Rafael,

On Thu, 3 Aug 2023, Rafael J. Wysocki wrote:

> Index: linux-pm/drivers/cpuidle/governors/teo.c
> ===================================================================
> --- linux-pm.orig/drivers/cpuidle/governors/teo.c
> +++ linux-pm/drivers/cpuidle/governors/teo.c
> @@ -166,6 +166,12 @@
> */
> #define NR_RECENT 9
>
> +/*
> + * Idle state target residency threshold used for deciding whether or not to
> + * check the time till the closest expected timer event.
> + */
> +#define RESIDENCY_THRESHOLD_NS (15 * NSEC_PER_USEC)
> +

I would like to understand why this residency threshold is a fixed value
and not related to TICK_NSEC. I'm sure there is a reason for it - but for
me it is not obvious. Can you please explain it to me?

Thanks,

Anna-Maria