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From: Thara Gopinath <thara.gopinath@linaro.org>
To: Randy Dunlap <rdunlap@infradead.org>,
	mingo@redhat.com, peterz@infradead.org, ionela.voinescu@arm.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rui.zhang@intel.com, qperret@google.com,
	daniel.lezcano@linaro.org, viresh.kumar@linaro.org,
	rostedt@goodmis.org, will@kernel.org, catalin.marinas@arm.com,
	sudeep.holla@arm.com, juri.lelli@redhat.com, corbet@lwn.net
Cc: linux-kernel@vger.kernel.org, amit.kachhap@gmail.com,
	javi.merino@kernel.org, amit.kucheria@verdurent.com
Subject: Re: [Patch v9 7/8] sched/fair: Enable tuning of decay period
Date: Mon, 3 Feb 2020 07:07:57 -0500	[thread overview]
Message-ID: <5E380D1D.7020500@linaro.org> (raw)
In-Reply-To: <4eb10687-1a62-cee3-7285-3f50cc023071@infradead.org>

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

  reply	other threads:[~2020-02-03 12:08 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-28 22:35 [Patch v9 0/8] Introduce Thermal Pressure Thara Gopinath
2020-01-28 22:36 ` [Patch v9 1/8] sched/pelt: Add support to track thermal pressure Thara Gopinath
2020-02-13 12:29   ` Amit Kucheria
2020-02-13 14:11     ` Thara Gopinath
2020-02-13 14:41       ` Amit Kucheria
2020-01-28 22:36 ` [Patch v9 2/8] sched/topology: Add hook to read per cpu " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 3/8] arm,arm64,drivers:Add infrastructure to store and update instantaneous " Thara Gopinath
2020-02-13 12:25   ` Amit Kucheria
2020-02-13 14:05     ` Thara Gopinath
2020-02-13 14:38       ` Amit Kucheria
2020-02-14 15:01         ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 4/8] sched/fair: Enable periodic update of average " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 5/8] sched/fair: update cpu_capacity to reflect " Thara Gopinath
2020-02-13 12:47   ` Amit Kucheria
2020-02-13 14:12     ` Thara Gopinath
2020-02-13 13:39   ` Amit Kucheria
2020-02-14 14:52     ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 6/8] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2020-01-28 22:36 ` [Patch v9 7/8] sched/fair: Enable tuning of decay period Thara Gopinath
2020-01-28 23:56   ` Randy Dunlap
2020-02-03 12:07     ` Thara Gopinath [this message]
2020-02-03 15:55       ` Peter Zijlstra
2020-02-04  8:39         ` Dietmar Eggemann
2020-02-07 22:42           ` Thara Gopinath
2020-02-10 11:59             ` Dietmar Eggemann
2020-02-13 13:54               ` Thara Gopinath
2020-02-14 10:26                 ` Dietmar Eggemann
2020-02-18 14:57                   ` Thara Gopinath
2020-02-19  9:14                     ` Dietmar Eggemann
2020-01-28 22:36 ` [Patch v9 8/8] arm64: Enable averaging of thermal pressure for arm64 based SoCs Thara Gopinath
2020-02-03  8:59   ` Dietmar Eggemann
2020-02-10 12:07 ` [Patch v9 0/8] Introduce Thermal Pressure Dietmar Eggemann

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