linux-kernel - Re: [PATCH v2 1/5] cpufreq/amd-pstate: Add dynamic energy performance preference

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Message-ID: <87d34e74-46e3-45c3-8f17-baf2feb50506@kernel.org>
Date: Tue, 18 Mar 2025 14:08:10 -0500
From: Mario Limonciello <superm1@...nel.org>
To: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
 "Gautham R . Shenoy" <gautham.shenoy@....com>,
 Perry Yuan <perry.yuan@....com>
Cc: "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>,
 "open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
 Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v2 1/5] cpufreq/amd-pstate: Add dynamic energy performance
 preference

On 3/11/2025 01:34, Dhananjay Ugwekar wrote:
> On 3/4/2025 8:53 PM, Mario Limonciello wrote:
>> From: Mario Limonciello <mario.limonciello@....com>
>>
>> Dynamic energy performance preference will change the EPP profile
>> based on whether the machine is running on AC or DC power.
>>
>> A notification chain from the power supply core is used to adjust
>> EPP values on plug in or plug out events.
>>
>> For non-server systems:
>>      * the default EPP for AC mode is `performance`.
>>      * the default EPP for DC mode is `balance_performance`.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>> v1->v2:
>>   * Change defaults to performance (AC) and balance_performance (DC)
>>   * Default Kconfig to disabled for now
>>   * Rebase on latest branch
>> ---
>>   Documentation/admin-guide/pm/amd-pstate.rst |  18 ++-
>>   drivers/cpufreq/Kconfig.x86                 |  12 ++
>>   drivers/cpufreq/amd-pstate.c                | 129 ++++++++++++++++++--
>>   drivers/cpufreq/amd-pstate.h                |   5 +-
>>   4 files changed, 155 insertions(+), 9 deletions(-)
>>
> [Snip]
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index e98ef41083ba1..f00fb4ba9f26e 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -36,6 +36,7 @@
>>   #include <linux/io.h>
>>   #include <linux/delay.h>
>>   #include <linux/uaccess.h>
>> +#include <linux/power_supply.h>
>>   #include <linux/static_call.h>
>>   #include <linux/topology.h>
>>   
>> @@ -86,6 +87,7 @@ static struct cpufreq_driver amd_pstate_driver;
>>   static struct cpufreq_driver amd_pstate_epp_driver;
>>   static int cppc_state = AMD_PSTATE_UNDEFINED;
>>   static bool amd_pstate_prefcore = true;
>> +static bool dynamic_epp = CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP;
> 
> Is there an #ifdef needed here? I see build error when X86_AMD_PSTATE_DYNAMIC_EPP is not set in config
> 

Ah yeah, I see the same too when I check that config.  Not sure why 
build robot didn't catch this.

Will add this for next version.

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index dcf6e36d693f8..824756ac0010e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -87,7 +87,11 @@ static struct cpufreq_driver amd_pstate_driver;
  static struct cpufreq_driver amd_pstate_epp_driver;
  static int cppc_state = AMD_PSTATE_UNDEFINED;
  static bool amd_pstate_prefcore = true;
+#ifdef CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP
  static bool dynamic_epp = CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP;
+#else
+static bool dynamic_epp = false;
+#endif
  static struct quirk_entry *quirks;

  /*