diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 18 | ||||
| -rw-r--r-- | Documentation/cpu-freq/cpu-drivers.txt | 6 | ||||
| -rw-r--r-- | Documentation/cpu-freq/user-guide.txt | 11 |
3 files changed, 32 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index a703b9e..974e29f 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -136,6 +136,24 @@ Description: Discover cpuidle policy and mechanism See files in Documentation/cpuidle/ for more information. +What: /sys/devices/system/cpu/cpu#/cpufreq/* +Date: pre-git history +Contact: cpufreq@vger.kernel.org +Description: Discover and change clock speed of CPUs + + Clock scaling allows you to change the clock speed of the + CPUs on the fly. This is a nice method to save battery + power, because the lower the clock speed, the less power + the CPU consumes. + + There are many knobs to tweak in this directory. + + See files in Documentation/cpu-freq/ for more information. + + In particular, read Documentation/cpu-freq/user-guide.txt + to learn how to control the knobs. + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt index 75a58d1..6c30e93 100644 --- a/Documentation/cpu-freq/cpu-drivers.txt +++ b/Documentation/cpu-freq/cpu-drivers.txt @@ -92,9 +92,9 @@ policy->cpuinfo.max_freq - the minimum and maximum frequency (in kHz) which is supported by this CPU policy->cpuinfo.transition_latency the time it takes on this CPU to - switch between two frequencies (if - appropriate, else specify - CPUFREQ_ETERNAL) + switch between two frequencies in + nanoseconds (if appropriate, else + specify CPUFREQ_ETERNAL) policy->cur The current operating frequency of this CPU (if appropriate) diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index 2a5b850..04f6b32 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -203,6 +203,17 @@ scaling_cur_freq : Current frequency of the CPU as determined by the frequency the kernel thinks the CPU runs at. +bios_limit : If the BIOS tells the OS to limit a CPU to + lower frequencies, the user can read out the + maximum available frequency from this file. + This typically can happen through (often not + intended) BIOS settings, restrictions + triggered through a service processor or other + BIOS/HW based implementations. + This does not cover thermal ACPI limitations + which can be detected through the generic + thermal driver. + If you have selected the "userspace" governor which allows you to set the CPU operating frequency to a specific value, you can read out the current frequency in |