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

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Date:   Thu, 23 Nov 2023 19:47:41 +0530
From:   Sumit Gupta <sumitg@...dia.com>
To:     Sudeep Holla <sudeep.holla@....com>
CC:     <rafael@...nel.org>, <rui.zhang@...el.com>, <lenb@...nel.org>,
        <lpieralisi@...nel.org>, <guohanjun@...wei.com>,
        <linux-acpi@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <treding@...dia.com>,
        <jonathanh@...dia.com>, <bbasu@...dia.com>, <sanjayc@...dia.com>,
        <ksitaraman@...dia.com>, <srikars@...dia.com>,
        <jbrasen@...dia.com>, Sumit Gupta <sumitg@...dia.com>
Subject: Re: [Patch v7] ACPI: processor: reduce CPUFREQ thermal reduction pctg
 for Tegra241



On 23/11/23 19:30, Sudeep Holla wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Thu, Nov 23, 2023 at 05:44:33PM +0530, Sumit Gupta wrote:
>> From: Srikar Srimath Tirumala <srikars@...dia.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@...dia.com>
>> Co-developed-by: Sumit Gupta <sumitg@...dia.com>
>> Signed-off-by: Sumit Gupta <sumitg@...dia.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@....com>
> 
> 
> [...]
> 

Thank you.

>> 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.
> 
> --
> Regards,
> Sudeep

Sure, will check and send a separate patch later on top.

Best Regards,
Sumit Gupta