diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 24 | ||||
| -rw-r--r-- | Documentation/acpi/namespace.txt | 9 | ||||
| -rw-r--r-- | Documentation/cpu-freq/boost.txt | 26 | ||||
| -rw-r--r-- | Documentation/cpu-freq/intel-pstate.txt | 40 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 |
5 files changed, 81 insertions, 21 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 468e4d48f884..d5a0d33c571f 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -200,3 +200,27 @@ Description: address and size of the percpu note. note of cpu#. crash_notes_size: size of the note of cpu#. + + +What: /sys/devices/system/cpu/intel_pstate/max_perf_pct + /sys/devices/system/cpu/intel_pstate/min_perf_pct + /sys/devices/system/cpu/intel_pstate/no_turbo +Date: February 2013 +Contact: linux-pm@vger.kernel.org +Description: Parameters for the Intel P-state driver + + Logic for selecting the current P-state in Intel + Sandybridge+ processors. The three knobs control + limits for the P-state that will be requested by the + driver. + + max_perf_pct: limits the maximum P state that will be requested by + the driver stated as a percentage of the available performance. + + min_perf_pct: limits the minimum P state that will be requested by + the driver stated as a percentage of the available performance. + + no_turbo: limits the driver to selecting P states below the turbo + frequency range. + + More details can be found in Documentation/cpu-freq/intel-pstate.txt diff --git a/Documentation/acpi/namespace.txt b/Documentation/acpi/namespace.txt index 260f6a3661fa..1860cb3865c6 100644 --- a/Documentation/acpi/namespace.txt +++ b/Documentation/acpi/namespace.txt @@ -235,10 +235,6 @@ Wysocki <rafael.j.wysocki@intel.com>. named object's type in the second column). In that case the object's directory in sysfs will contain the 'path' attribute whose value is the full path to the node from the namespace root. - struct acpi_device objects are created for the ACPI namespace nodes - whose _STA control methods return PRESENT or FUNCTIONING. The power - resource nodes or nodes without _STA are assumed to be both PRESENT - and FUNCTIONING. F: The struct acpi_device object is created for a fixed hardware feature (as indicated by the fixed feature flag's name in the second @@ -340,7 +336,7 @@ Wysocki <rafael.j.wysocki@intel.com>. | +-------------+-------+----------------+ | | | | +- - - - - - - +- - - - - - +- - - - - - - -+ - | +-| * PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: | + | +-| PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: | | | +- - - - - - - +- - - - - - +- - - - - - - -+ | | | | +------------+------------+-----------------------+ @@ -390,6 +386,3 @@ Wysocki <rafael.j.wysocki@intel.com>. attribute (as described earlier in this document). NOTE: N/A indicates the device object does not have the 'path' or the 'modalias' attribute. - NOTE: The PNP0C0D device listed above is highlighted (marked by "*") - to indicate it will be created only when its _STA methods return - PRESENT or FUNCTIONING. diff --git a/Documentation/cpu-freq/boost.txt b/Documentation/cpu-freq/boost.txt index 9b4edfcf486f..dd62e1334f0a 100644 --- a/Documentation/cpu-freq/boost.txt +++ b/Documentation/cpu-freq/boost.txt @@ -17,8 +17,8 @@ Introduction Some CPUs support a functionality to raise the operating frequency of some cores in a multi-core package if certain conditions apply, mostly if the whole chip is not fully utilized and below it's intended thermal -budget. This is done without operating system control by a combination -of hardware and firmware. +budget. The decision about boost disable/enable is made either at hardware +(e.g. x86) or software (e.g ARM). On Intel CPUs this is called "Turbo Boost", AMD calls it "Turbo-Core", in technical documentation "Core performance boost". In Linux we use the term "boost" for convenience. @@ -48,24 +48,24 @@ be desirable: User controlled switch ---------------------- -To allow the user to toggle the boosting functionality, the acpi-cpufreq -driver exports a sysfs knob to disable it. There is a file: +To allow the user to toggle the boosting functionality, the cpufreq core +driver exports a sysfs knob to enable or disable it. There is a file: /sys/devices/system/cpu/cpufreq/boost which can either read "0" (boosting disabled) or "1" (boosting enabled). -Reading the file is always supported, even if the processor does not -support boosting. In this case the file will be read-only and always -reads as "0". Explicitly changing the permissions and writing to that -file anyway will return EINVAL. +The file is exported only when cpufreq driver supports boosting. +Explicitly changing the permissions and writing to that file anyway will +return EINVAL. On supported CPUs one can write either a "0" or a "1" into this file. This will either disable the boost functionality on all cores in the -whole system (0) or will allow the hardware to boost at will (1). +whole system (0) or will allow the software or hardware to boost at will +(1). Writing a "1" does not explicitly boost the system, but just allows the -CPU (and the firmware) to boost at their discretion. Some implementations -take external factors like the chip's temperature into account, so -boosting once does not necessarily mean that it will occur every time -even using the exact same software setup. +CPU to boost at their discretion. Some implementations take external +factors like the chip's temperature into account, so boosting once does +not necessarily mean that it will occur every time even using the exact +same software setup. AMD legacy cpb switch diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt new file mode 100644 index 000000000000..e742d21dbd96 --- /dev/null +++ b/Documentation/cpu-freq/intel-pstate.txt @@ -0,0 +1,40 @@ +Intel P-state driver +-------------------- + +This driver implements a scaling driver with an internal governor for +Intel Core processors. The driver follows the same model as the +Transmeta scaling driver (longrun.c) and implements the setpolicy() +instead of target(). Scaling drivers that implement setpolicy() are +assumed to implement internal governors by the cpufreq core. All the +logic for selecting the current P state is contained within the +driver; no external governor is used by the cpufreq core. + +Intel SandyBridge+ processors are supported. + +New sysfs files for controlling P state selection have been added to +/sys/devices/system/cpu/intel_pstate/ + + max_perf_pct: limits the maximum P state that will be requested by + the driver stated as a percentage of the available performance. + + min_perf_pct: limits the minimum P state that will be requested by + the driver stated as a percentage of the available performance. + + no_turbo: limits the driver to selecting P states below the turbo + frequency range. + +For contemporary Intel processors, the frequency is controlled by the +processor itself and the P-states exposed to software are related to +performance levels. The idea that frequency can be set to a single +frequency is fiction for Intel Core processors. Even if the scaling +driver selects a single P state the actual frequency the processor +will run at is selected by the processor itself. + +New debugfs files have also been added to /sys/kernel/debug/pstate_snb/ + + deadband + d_gain_pct + i_gain_pct + p_gain_pct + sample_rate_ms + setpoint diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 44738564b2ee..be6ba33d4ff1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -343,6 +343,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. no: ACPI OperationRegions are not marked as reserved, no further checks are performed. + acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump + kernels. + add_efi_memmap [EFI; X86] Include EFI memory map in kernel's map of available physical RAM. |