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howtos:hardware:cpu_frequency_scaling [2013/12/16 22:33 (UTC)] – small redundant section metaschima | howtos:hardware:cpu_frequency_scaling [2013/12/16 23:49 (UTC)] – [Kernel Config Requirements] metaschima | ||
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===== Kernel Config Requirements ===== | ===== Kernel Config Requirements ===== | ||
The kernel options for CPU frequency scaling are as follows. You need both a governor (one set to default) and a driver. The Slackware default governor is ' | The kernel options for CPU frequency scaling are as follows. You need both a governor (one set to default) and a driver. The Slackware default governor is ' | ||
- | * Power management and ACPI options | + | |
* CPU Frequency scaling | * CPU Frequency scaling | ||
* CPU Frequency scaling (CPU_FREQ [=y]) | * CPU Frequency scaling (CPU_FREQ [=y]) | ||
- | * ' | + | * ' |
- | * ' | + | * ' |
- | * ' | + | * ' |
- | * ' | + | * ' |
- | * ' | + | * ' |
* x86 CPU frequency scaling drivers | * x86 CPU frequency scaling drivers | ||
- | * Intel P state control (X86_INTEL_PSTATE [=n]) This driver is mutually exclusive with CONFIG_X86_ACPI_CPUFREQ. It is a newer driver for Sandy Bridge processors and [[https:// | + | * Intel P state control (X86_INTEL_PSTATE [=n])\\ This driver is mutually exclusive with CONFIG_X86_ACPI_CPUFREQ. It is a newer driver for Sandy Bridge processors and [[https:// |
- | * Processor Clocking Control interface driver (CONFIG_X86_PCC_CPUFREQ) This is only required for HP ProLiant servers, which using this interface. Otherwise, disable it. | + | * Processor Clocking Control interface driver (CONFIG_X86_PCC_CPUFREQ)\\ This is only required for HP ProLiant servers, which using this interface. Otherwise, disable it. |
- | * ACPI Processor P-States driver (CONFIG_X86_ACPI_CPUFREQ [=y]) This is the recommended driver for newer CPUs Intel (Enhanced) Speedstep enabled and AMD K10 and newer. | + | * ACPI Processor P-States driver (CONFIG_X86_ACPI_CPUFREQ [=y])\\ This is the recommended driver for newer CPUs Intel (Enhanced) Speedstep enabled and AMD K10 and newer. |
- | * AMD Opteron/ | + | * AMD Opteron/ |
- | * Intel Enhanced SpeedStep (deprecated) (CONFIG_X86_SPEEDSTEP_CENTRINO [=n] This is a deprecated option that has been superseded by CONFIG_X86_ACPI_CPUFREQ, | + | * Intel Enhanced SpeedStep (deprecated) (CONFIG_X86_SPEEDSTEP_CENTRINO [=n])\\ This is a deprecated option that has been superseded by CONFIG_X86_ACPI_CPUFREQ, |
- | * Intel Pentium 4 clock modulation (CONFIG_X86_P4_CLOCKMOD [=n]) This is a hack for Pentium 4s that may cause severe slowdowns and noticeable latencies, so disable it. | + | * Intel Pentium 4 clock modulation (CONFIG_X86_P4_CLOCKMOD [=n])\\ This is a hack for Pentium 4s that may cause severe slowdowns and noticeable latencies, so disable it. |
<note important> | <note important> | ||
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as long as the interface exists. | as long as the interface exists. | ||
===== Further reading ===== | ===== Further reading ===== | ||
- | I recommend reading the manpages for cpufreq-info and cpufreq-set. | + | The manpages for '' |
+ | |||
+ | The kernel | ||
A decent explanation of P states and how they are handled in the kernel: https:// | A decent explanation of P states and how they are handled in the kernel: https:// |