Messages in this thread | | | Subject | Re: [Patch v9 7/8] sched/fair: Enable tuning of decay period | From | Thara Gopinath <> | Date | Mon, 3 Feb 2020 07:07:57 -0500 |
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On 01/28/2020 06:56 PM, Randy Dunlap wrote: > 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?
Thanks for the review. 0 does not disable "thermal pressure" feature. 0 means the default decay period for averaging PELT signals (which is usually 32 but configurable) will also be applied for thermal pressure signal. A shift will shift the default decay period.
You are right. It needs more explanation here. I will fix it and send v10.
> >> 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. >
-- Warm Regards Thara
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