Re: [Patch v9 7/8] sched/fair: Enable tuning of decay period

From: Randy Dunlap
Date: Tue Jan 28 2020 - 18:57:08 EST


Hi,

On 1/28/20 2:36 PM, Thara Gopinath wrote:
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index e35b28e..be4147b 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4376,6 +4376,11 @@
> incurs a small amount of overhead in the scheduler
> but is useful for debugging and performance tuning.
>
> + sched_thermal_decay_shift=
> + [KNL, SMP] Set decay shift for thermal pressure signal.
> + Format: integer between 0 and 10
> + Default is 0.
> +

That tells an admin [or any reader] almost nothing about this kernel parameter
or what it does. And nothing about what unit the value is in.
Does the value 0 disable this feature?

> skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
> xtime_lock contention on larger systems, and/or RCU lock
> contention on all systems with CONFIG_MAXSMP set.


thanks.
--
~Randy