Loading Documentation/admin-guide/pm/intel_pstate.rst +19 −13 Original line number Diff line number Diff line Loading @@ -62,9 +62,10 @@ on the capabilities of the processor. Active Mode ----------- This is the default operation mode of ``intel_pstate``. If it works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_pstate". This is the default operation mode of ``intel_pstate`` for processors with hardware-managed P-states (HWP) support. If it works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_pstate". In this mode the driver bypasses the scaling governors layer of ``CPUFreq`` and provides its own scaling algorithms for P-state selection. Those algorithms Loading Loading @@ -138,12 +139,13 @@ internal P-state selection logic to be less performance-focused. Active Mode Without HWP ~~~~~~~~~~~~~~~~~~~~~~~ This is the default operation mode for processors that do not support the HWP feature. It also is used by default with the ``intel_pstate=no_hwp`` argument in the kernel command line. However, in this mode ``intel_pstate`` may refuse to work with the given processor if it does not recognize it. [Note that ``intel_pstate`` will never refuse to work with any processor with the HWP feature enabled.] This operation mode is optional for processors that do not support the HWP feature or when the ``intel_pstate=no_hwp`` argument is passed to the kernel in the command line. The active mode is used in those cases if the ``intel_pstate=active`` argument is passed to the kernel in the command line. In this mode ``intel_pstate`` may refuse to work with processors that are not recognized by it. [Note that ``intel_pstate`` will never refuse to work with any processor with the HWP feature enabled.] In this mode ``intel_pstate`` registers utilization update callbacks with the CPU scheduler in order to run a P-state selection algorithm, either Loading Loading @@ -188,10 +190,14 @@ is not set. Passive Mode ------------ This mode is used if the ``intel_pstate=passive`` argument is passed to the kernel in the command line (it implies the ``intel_pstate=no_hwp`` setting too). Like in the active mode without HWP support, in this mode ``intel_pstate`` may refuse to work with the given processor if it does not recognize it. This is the default operation mode of ``intel_pstate`` for processors without hardware-managed P-states (HWP) support. It is always used if the ``intel_pstate=passive`` argument is passed to the kernel in the command line regardless of whether or not the given processor supports HWP. [Note that the ``intel_pstate=no_hwp`` setting implies ``intel_pstate=passive`` if it is used without ``intel_pstate=active``.] Like in the active mode without HWP support, in this mode ``intel_pstate`` may refuse to work with processors that are not recognized by it. If the driver works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_cpufreq". Loading drivers/cpufreq/intel_pstate.c +2 −1 Original line number Diff line number Diff line Loading @@ -2771,6 +2771,8 @@ static int __init intel_pstate_init(void) pr_info("Invalid MSRs\n"); return -ENODEV; } /* Without HWP start in the passive mode. */ default_driver = &intel_cpufreq; hwp_cpu_matched: /* Loading Loading @@ -2816,7 +2818,6 @@ static int __init intel_pstate_setup(char *str) if (!strcmp(str, "disable")) { no_load = 1; } else if (!strcmp(str, "passive")) { pr_info("Passive mode enabled\n"); default_driver = &intel_cpufreq; no_hwp = 1; } Loading Loading
Documentation/admin-guide/pm/intel_pstate.rst +19 −13 Original line number Diff line number Diff line Loading @@ -62,9 +62,10 @@ on the capabilities of the processor. Active Mode ----------- This is the default operation mode of ``intel_pstate``. If it works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_pstate". This is the default operation mode of ``intel_pstate`` for processors with hardware-managed P-states (HWP) support. If it works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_pstate". In this mode the driver bypasses the scaling governors layer of ``CPUFreq`` and provides its own scaling algorithms for P-state selection. Those algorithms Loading Loading @@ -138,12 +139,13 @@ internal P-state selection logic to be less performance-focused. Active Mode Without HWP ~~~~~~~~~~~~~~~~~~~~~~~ This is the default operation mode for processors that do not support the HWP feature. It also is used by default with the ``intel_pstate=no_hwp`` argument in the kernel command line. However, in this mode ``intel_pstate`` may refuse to work with the given processor if it does not recognize it. [Note that ``intel_pstate`` will never refuse to work with any processor with the HWP feature enabled.] This operation mode is optional for processors that do not support the HWP feature or when the ``intel_pstate=no_hwp`` argument is passed to the kernel in the command line. The active mode is used in those cases if the ``intel_pstate=active`` argument is passed to the kernel in the command line. In this mode ``intel_pstate`` may refuse to work with processors that are not recognized by it. [Note that ``intel_pstate`` will never refuse to work with any processor with the HWP feature enabled.] In this mode ``intel_pstate`` registers utilization update callbacks with the CPU scheduler in order to run a P-state selection algorithm, either Loading Loading @@ -188,10 +190,14 @@ is not set. Passive Mode ------------ This mode is used if the ``intel_pstate=passive`` argument is passed to the kernel in the command line (it implies the ``intel_pstate=no_hwp`` setting too). Like in the active mode without HWP support, in this mode ``intel_pstate`` may refuse to work with the given processor if it does not recognize it. This is the default operation mode of ``intel_pstate`` for processors without hardware-managed P-states (HWP) support. It is always used if the ``intel_pstate=passive`` argument is passed to the kernel in the command line regardless of whether or not the given processor supports HWP. [Note that the ``intel_pstate=no_hwp`` setting implies ``intel_pstate=passive`` if it is used without ``intel_pstate=active``.] Like in the active mode without HWP support, in this mode ``intel_pstate`` may refuse to work with processors that are not recognized by it. If the driver works in this mode, the ``scaling_driver`` policy attribute in ``sysfs`` for all ``CPUFreq`` policies contains the string "intel_cpufreq". Loading
drivers/cpufreq/intel_pstate.c +2 −1 Original line number Diff line number Diff line Loading @@ -2771,6 +2771,8 @@ static int __init intel_pstate_init(void) pr_info("Invalid MSRs\n"); return -ENODEV; } /* Without HWP start in the passive mode. */ default_driver = &intel_cpufreq; hwp_cpu_matched: /* Loading Loading @@ -2816,7 +2818,6 @@ static int __init intel_pstate_setup(char *str) if (!strcmp(str, "disable")) { no_load = 1; } else if (!strcmp(str, "passive")) { pr_info("Passive mode enabled\n"); default_driver = &intel_cpufreq; no_hwp = 1; } Loading
