power.rst
author Oleksandr Gavenko <gavenkoa@gmail.com>
Thu, 12 Aug 2010 21:08:07 +0300
changeset 498 71ee42742a81
parent 497 8550e7dc31e1
permissions -rw-r--r--
Enhanced Intel SpeedStepВ® Technology and Demand-Based Switching on Linux
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
498
71ee42742a81 Enhanced Intel SpeedStepВ® Technology and Demand-Based Switching on Linux
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 497
diff changeset
     1
497
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
     2
-*- mode: outline; coding: utf-8 -*-
429
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     3
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     4
* ACPI power states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     5
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     6
  http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     7
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     8
** Global states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
     9
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    10
 * G0 (S0) Working
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    11
 * G1 Sleeping (subdivides into the four states S1 through S4)
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    12
   * S1: All processor caches are flushed, and the CPU(s) stop executing
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    13
     instructions. Power to the CPU(s) and RAM is maintained; devices that do
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    14
     not indicate they must remain on may be powered down.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    15
   * S2: CPU powered off.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    16
   * S3: Commonly referred to as Standby, Sleep, or Suspend to RAM. RAM
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    17
     remains powered.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    18
   * S4: Hibernation or Suspend to Disk. All content of main memory is saved
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    19
     to non-volatile memory such as a hard drive, and is powered down.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    20
 * G2 (S5) Soft Off. G2, S5, and Soft Off are synonyms. G2 is almost the same
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    21
   as G3 Mechanical Off, but some components remain powered so the computer
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    22
   can "wake" from input from the keyboard, clock, modem, LAN, or USB device.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    23
 * G3 Mechanical Off: The computer's power consumption approaches close to
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    24
   zero, to the point that the power cord can be removed and the system is
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    25
   safe for dis-assembly (typically, only the real-time clock is running off
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    26
   its own small battery).
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    27
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    28
** System states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    29
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    30
 * S0 Working (G0), Processor in C0-C3, full context save RAM maintained
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    31
 * S1 Sleeping with processor context maintained, RAM maintained
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    32
 * S2 Sleeping with processor content not necessarily maintained, RAM
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    33
   maintained, most devices in D3
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    34
 * S3 Sleeping, lower than S2, RAM maintained, most devices in D3
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    35
 * S4 Sleeping, lower than S3, RAM not maintained, most devices in D3
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    36
 * S5 Sleeping, lower than S4, no context saved, reboot necessary
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    37
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    38
** Device states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    39
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    40
 * D0 Fully-On is the operating state.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    41
 * D1 and D2 are intermediate power-states whose definition varies by device.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    42
 * D3 Off has the device powered off and unresponsive to its bus.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    43
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    44
** Processor states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    45
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    46
 * C0 is the operating state.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    47
 * C1 (often known as Halt) is a state where the processor is not executing
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    48
   instructions, but can return to an executing state essentially
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    49
   instantaneously. All ACPI-conformant processors must support this power state.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    50
 * C2 (often known as Stop-Clock) is a state where the processor maintains all
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    51
   software-visible state, but may take longer to wake up. This processor
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    52
   state is optional.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    53
 * C3 (often known as Sleep) is a state where the processor does not need to
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    54
   keep its cache coherent, but maintains other state. Some processors have
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    55
   variations on the C3 state (Deep Sleep, Deeper Sleep, etc.) that differ in
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    56
   how long it takes to wake the processor. This processor state is optional.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    57
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    58
** Performance states.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    59
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    60
 * P0 max power and frequency.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    61
 * P1 less than P0, voltage/frequency scaled.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    62
 * Pn less than P(n-1), voltage/frequency scaled.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    63
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    64
* Control power schema under Windows.
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    65
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    66
Use powercfg utility. To se current state:
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    67
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    68
  cmd> powercfg /QUERY
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    69
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    70
To see all available states:
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    71
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    72
  cmd> powercfg /LIST
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    73
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    74
To restore power configurtion:
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    75
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    76
  cmd> powercfg /RestoreDefaultPolicies
23003b488928 ACPI power states. Control power schema under Windows.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents:
diff changeset
    77
497
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    78
* Intel.
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    79
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    80
** Intel Speedstep® Technology.
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    81
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    82
  http://www.intel.com/support/processors/sb/CS-028855.htm
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    83
                Frequently asked questions for Intel Speedstep® Technology
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    84
  http://www.intel.com/p/en_US/support/highlights/processors/frequencyid
8550e7dc31e1 Intel SpeedstepВ® Technology.
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 429
diff changeset
    85
                Intel® Processor Frequency ID Utility
498
71ee42742a81 Enhanced Intel SpeedStepВ® Technology and Demand-Based Switching on Linux
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 497
diff changeset
    86
  http://software.intel.com/en-us/articles/enhanced-intel-speedstepr-technology-and-demand-based-switching-on-linux
71ee42742a81 Enhanced Intel SpeedStepВ® Technology and Demand-Based Switching on Linux
Oleksandr Gavenko <gavenkoa@gmail.com>
parents: 497
diff changeset
    87
                Enhanced Intel SpeedStep® Technology and Demand-Based Switching on Linux