Re: [Patch v7] ACPI: processor: reduce CPUFREQ thermal reduction pctg for Tegra241

From: Sumit Gupta <sumitg@nvidia.com>
To: <rafael@kernel.org>
Cc: <rui.zhang@intel.com>, <lenb@kernel.org>, <lpieralisi@kernel.org>,
	"Sudeep Holla" <sudeep.holla@arm.com>,
	<linux-acpi@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <treding@nvidia.com>,
	<jonathanh@nvidia.com>, <bbasu@nvidia.com>, <sanjayc@nvidia.com>,
	<ksitaraman@nvidia.com>, <srikars@nvidia.com>,
	<jbrasen@nvidia.com>, "Hanjun Guo" <guohanjun@huawei.com>,
	Sumit Gupta <sumitg@nvidia.com>
Subject: Re: [Patch v7] ACPI: processor: reduce CPUFREQ thermal reduction pctg for Tegra241
Date: Wed, 6 Dec 2023 15:43:40 +0530	[thread overview]
Message-ID: <fd877ca8-6deb-9bc1-877d-57817a8913ac@nvidia.com> (raw)
In-Reply-To: <6ccd1598-3c8b-1290-9494-01a3cdbb3003@huawei.com>

>>> From: Srikar Srimath Tirumala <srikars@nvidia.com>
>>>
>>> Current implementation of processor_thermal performs software throttling
>>> in fixed steps of "20%" which can be too coarse for some platforms.
>>> We observed some performance gain after reducing the throttle 
>>> percentage.
>>> Change the CPUFREQ thermal reduction percentage and maximum thermal 
>>> steps
>>> to be configurable. Also, update the default values of both for Nvidia
>>> Tegra241 (Grace) SoC. The thermal reduction percentage is reduced to 
>>> "5%"
>>> and accordingly the maximum number of thermal steps are increased as 
>>> they
>>> are derived from the reduction percentage.
>>>
>>> Signed-off-by: Srikar Srimath Tirumala <srikars@nvidia.com>
>>> Co-developed-by: Sumit Gupta <sumitg@nvidia.com>
>>> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
>>> ---
>>>
>>> Sending this patch separately as the other patch in the series is
>>> applied by Rafael in v6[1]. Revision history before this version is
>>> in the cover letter of v6[1].
>>>
>>> Please review and provide ACK if looks fine.
>>>
>>
>> For arm64 specific changes(a minor nit below though),
>>
>> Acked-by: Sudeep Holla <sudeep.holla@arm.com>
>>
>>
>> [...]
>>
>>> diff --git a/drivers/acpi/arm64/thermal_cpufreq.c 
>>> b/drivers/acpi/arm64/thermal_cpufreq.c
>>> new file mode 100644
>>> index 000000000000..d524f2cd6044
>>> --- /dev/null
>>> +++ b/drivers/acpi/arm64/thermal_cpufreq.c
>>> @@ -0,0 +1,20 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +#include <linux/acpi.h>
>>> +
>>> +#include "../internal.h"
>>> +
>>> +#define SMCCC_SOC_ID_T241      0x036b0241
>>> +
>>
>> [nit] We really need to find better place to define this globally and not
>> locally at each usage site like this. We already have it in GICv3 driver.
>> But that can come as a cleanup later if it causes issue for merging this
>> change.
> 
> Agreed.
> 
> Looks good to me as well.
> 
> Acked-by: Hanjun Guo <guohanjun@huawei.com>
> 

Hi Rafael,

If the change seems fine, could you please apply this patch?

Thanks,
Sumit

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