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Thread: How to lock the CPU at a lower frequency when running on battery power?

  1. #1

    Default How to lock the CPU at a lower frequency when running on battery power?

    I really need to find a way to reduce CPU frequency when I'm running on battery power. I watch movies while running on battery, and the CPU constantly runs at near full speed, this causes the fans to spin up (more speed= more power consumption= more heat), and a continuous spinning fan takes a large bite out of my battery runtime- so much so I could watch videos for almost 6.5 to 7.00 hours (brightness set to minimum, CPU clocking at 0.80 GHz (fixed), and the fan completely turned off) in Win 10, and now only 3 hours in opensuse.

    I have come across some tutorials on how to do this, but they're either written for some other Linux and/or are too technical for me to keep up with.

    Basically I want the laptop to use dynamic frequency scaling when running on AC power, and switch to a lower (fixed) frequency when AC power is removed. I don't want to type in commands every time I unplug/ re-plug the AC adapter, I want opensuse to do this switching automatically when it detects a change in power source.

    All my problems with OpenSuse have either been solved or I have found a workaround- this is the ONLY thing that's bugging me.

    If anyone can help, it would be great.
    Last edited by johnwinchester; 14-Apr-2018 at 17:09. Reason: fix typo

  2. #2

    Default Re: How to lock the CPU at a lower frequency when running on battery power?

    In desperation, I downloaded a program called tlp from yast.

    here's the output of lscpu



    And here's my /etc/default/tlp file


    Code:
    TLP_ENABLE=1
    
    # Operation mode when no power supply can be detected: AC, BAT
    # Concerns some desktop and embedded hardware only.
    TLP_DEFAULT_MODE=AC
    
    
    # Operation mode select: 0=depend on power source, 1=always use TLP_DEFAULT_MODE
    # Hint: use in conjunction with TLP_DEFAULT_MODE=BAT for BAT settings on AC
    TLP_PERSISTENT_DEFAULT=0
    
    
    # Seconds laptop mode has to wait after the disk goes idle before doing a sync.
    # Non-zero value enables, zero disables laptop mode.
    DISK_IDLE_SECS_ON_AC=0
    DISK_IDLE_SECS_ON_BAT=0
    
    
    # Dirty page values (timeouts in secs).
    MAX_LOST_WORK_SECS_ON_AC=15
    MAX_LOST_WORK_SECS_ON_BAT=60
    
    
    # Hint: CPU parameters below are disabled by default, remove the leading #
    # to enable them, otherwise kernel default values are used.
    
    
    # Select a CPU frequency scaling governor.
    # Intel Core i processor with intel_pstate driver:
    #   powersave(*), performance
    # Older hardware with acpi-cpufreq driver:
    #   ondemand(*), powersave, performance, conservative, schedutil
    # (*) is recommended.
    # Hint: use tlp-stat -p to show the active driver and available governors.
    # Important:
    #   You *must* disable your distribution's governor settings or conflicts will
    #   occur. ondemand is sufficient for *almost all* workloads, you should know
    #   what you're doing!
    CPU_SCALING_GOVERNOR_ON_AC=performance
    CPU_SCALING_GOVERNOR_ON_BAT=powersave
    
    
    # Set the min/max frequency available for the scaling governor.
    # Possible values strongly depend on your CPU. For available frequencies see
    # the output of tlp-stat -p.
    #CPU_SCALING_MIN_FREQ_ON_AC=500000
    #CPU_SCALING_MAX_FREQ_ON_AC=1700000
    #CPU_SCALING_MIN_FREQ_ON_BAT=500000
    #CPU_SCALING_MAX_FREQ_ON_BAT=500000
    
    
    # Set energy performance hints (HWP) for Intel P-state governor:
    #   default, performance, balance_performance, balance_power, power
    # Values are given in order of increasing power saving.
    # Note: Intel Skylake or newer CPU and Kernel >= 4.10 required.
    CPU_HWP_ON_AC=balance_performance
    CPU_HWP_ON_BAT=balance_power
    
    
    # Set Intel P-state performance: 0..100 (%)
    # Limit the max/min P-state to control the power dissipation of the CPU.
    # Values are stated as a percentage of the available performance.
    # Requires an Intel Core i processor with intel_pstate driver.
    CPU_MIN_PERF_ON_AC=0
    CPU_MAX_PERF_ON_AC=100
    CPU_MIN_PERF_ON_BAT=0
    CPU_MAX_PERF_ON_BAT=30
    
    
    # Set the CPU "turbo boost" feature: 0=disable, 1=allow
    # Requires an Intel Core i processor.
    # Important:
    # - This may conflict with your distribution's governor settings
    # - A value of 1 does *not* activate boosting, it just allows it
    #CPU_BOOST_ON_AC=1
    #CPU_BOOST_ON_BAT=0
    
    
    # Minimize number of used CPU cores/hyper-threads under light load conditions
    SCHED_POWERSAVE_ON_AC=0
    SCHED_POWERSAVE_ON_BAT=1
    
    
    # Kernel NMI Watchdog:
    #   0=disable (default, saves power), 1=enable (for kernel debugging only)
    NMI_WATCHDOG=0
    
    
    # Change CPU voltages aka "undervolting" - Kernel with PHC patch required
    # Frequency voltage pairs are written to:
    #   /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
    # CAUTION: only use this, if you thoroughly understand what you are doing!
    #PHC_CONTROLS="F:V F:V F:V F:V"
    
    
    # Set CPU performance versus energy savings policy:
    #   performance, normal, powersave
    # Requires kernel module msr and x86_energy_perf_policy from linux-tools
    ENERGY_PERF_POLICY_ON_AC=performance
    ENERGY_PERF_POLICY_ON_BAT=powersave
    
    
    # Hard disk devices; separate multiple devices with spaces (default: sda).
    # Devices can be specified by disk ID also (lookup with: tlp diskid).
    DISK_DEVICES="sda sdb"
    
    
    # Hard disk advanced power management level: 1..254, 255 (max saving, min, off)
    # Levels 1..127 may spin down the disk; 255 allowable on most drives.
    # Separate values for multiple disks with spaces. Use the special value 'keep'
    # to keep the hardware default for the particular disk.
    DISK_APM_LEVEL_ON_AC="254 254"
    DISK_APM_LEVEL_ON_BAT="128 128"
    
    
    # Hard disk spin down timeout:
    #   0:        spin down disabled
    #   1..240:   timeouts from 5s to 20min (in units of 5s)
    #   241..251: timeouts from 30min to 5.5 hours (in units of 30min)
    # See 'man hdparm' for details.
    # Separate values for multiple disks with spaces. Use the special value 'keep'
    # to keep the hardware default for the particular disk.
    #DISK_SPINDOWN_TIMEOUT_ON_AC="0 0"
    #DISK_SPINDOWN_TIMEOUT_ON_BAT="0 0"
    
    
    # Select IO scheduler for the disk devices: cfq, deadline, noop (Default: cfq);
    # Separate values for multiple disks with spaces. Use the special value 'keep'
    # to keep the kernel default scheduler for the particular disk.
    #DISK_IOSCHED="cfq cfq"
    
    
    # SATA aggressive link power management (ALPM):
    #   min_power, medium_power, max_performance
    SATA_LINKPWR_ON_AC=max_performance
    SATA_LINKPWR_ON_BAT=min_power
    
    
    # Exclude SATA host devices from link power management.
    # Separate multiple hosts with spaces.
    #SATA_LINKPWR_BLACKLIST="host1"
    
    
    # Runtime Power Management for AHCI controllers and disks:
    #   on=disable, auto=enable
    # EXPERIMENTAL ** WARNING: auto will most likely cause system lockups/data loss
    #AHCI_RUNTIME_PM_ON_AC=on
    #AHCI_RUNTIME_PM_ON_BAT=on
    
    
    # Seconds of inactivity before disk is suspended
    AHCI_RUNTIME_PM_TIMEOUT=15
    
    
    # PCI Express Active State Power Management (PCIe ASPM):
    #   default, performance, powersave
    PCIE_ASPM_ON_AC=performance
    PCIE_ASPM_ON_BAT=powersave
    
    
    # Radeon graphics clock speed (profile method): low, mid, high, auto, default;
    # auto = mid on BAT, high on AC; default = use hardware defaults.
    # (Kernel >= 2.6.35 only, open-source radeon driver explicitly)
    RADEON_POWER_PROFILE_ON_AC=high
    RADEON_POWER_PROFILE_ON_BAT=low
    
    
    # Radeon dynamic power management method (DPM): battery, performance
    # (Kernel >= 3.11 only, requires boot option radeon.dpm=1)
    RADEON_DPM_STATE_ON_AC=performance
    RADEON_DPM_STATE_ON_BAT=battery
    
    
    # Radeon DPM performance level: auto, low, high; auto is recommended.
    RADEON_DPM_PERF_LEVEL_ON_AC=auto
    RADEON_DPM_PERF_LEVEL_ON_BAT=auto
    
    
    # WiFi power saving mode: on=enable, off=disable; not supported by all adapters.
    WIFI_PWR_ON_AC=off
    WIFI_PWR_ON_BAT=on
    
    
    # Disable wake on LAN: Y/N
    WOL_DISABLE=Y
    
    
    # Enable audio power saving for Intel HDA, AC97 devices (timeout in secs).
    # A value of 0 disables, >=1 enables power saving.
    SOUND_POWER_SAVE_ON_AC=0
    SOUND_POWER_SAVE_ON_BAT=1
    
    
    # Disable controller too (HDA only): Y/N
    SOUND_POWER_SAVE_CONTROLLER=Y
    
    
    # Power off optical drive in UltraBay/MediaBay: 0=disable, 1=enable.
    # Drive can be powered on again by releasing (and reinserting) the eject lever
    # or by pressing the disc eject button on newer models.
    # Note: an UltraBay/MediaBay hard disk is never powered off.
    BAY_POWEROFF_ON_AC=0
    BAY_POWEROFF_ON_BAT=0
    # Optical drive device to power off (default sr0).
    BAY_DEVICE="sr0"
    
    
    # Runtime Power Management for PCI(e) bus devices: on=disable, auto=enable
    RUNTIME_PM_ON_AC=on
    RUNTIME_PM_ON_BAT=auto
    
    
    # Exclude PCI(e) device adresses the following list from Runtime PM
    # (separate with spaces). Use lspci to get the adresses (1st column).
    #RUNTIME_PM_BLACKLIST="bb:dd.f 11:22.3 44:55.6"
    
    
    # Exclude PCI(e) devices assigned to the listed drivers from Runtime PM.
    # Default when unconfigured is "amdgpu nouveau nvidia radeon" which
    # prevents accidential power-on of dGPU in hybrid graphics setups.
    # Use "" to disable the feature completely.
    # Separate multiple drivers with spaces.
    #RUNTIME_PM_DRIVER_BLACKLIST="amdgpu nouveau nvidia radeon"
    
    
    # Set to 0 to disable, 1 to enable USB autosuspend feature.
    USB_AUTOSUSPEND=1
    
    
    # Exclude listed devices from USB autosuspend (separate with spaces).
    # Use lsusb to get the ids.
    # Note: input devices (usbhid) are excluded automatically
    #USB_BLACKLIST="1111:2222 3333:4444"
    
    
    # Bluetooth devices are excluded from USB autosuspend:
    #   0=do not exclude, 1=exclude
    USB_BLACKLIST_BTUSB=0
    
    
    # Phone devices are excluded from USB autosuspend:
    #   0=do not exclude, 1=exclude (enable charging)
    USB_BLACKLIST_PHONE=0
    
    
    # WWAN devices are excluded from USB autosuspend:
    #   0=do not exclude, 1=exclude
    USB_BLACKLIST_WWAN=1
    
    
    # Include listed devices into USB autosuspend even if already excluded
    # by the blacklists above (separate with spaces).
    # Use lsusb to get the ids.
    #USB_WHITELIST="1111:2222 3333:4444"
    
    
    # Set to 1 to disable autosuspend before shutdown, 0 to do nothing
    # (workaround for USB devices that cause shutdown problems).
    #USB_AUTOSUSPEND_DISABLE_ON_SHUTDOWN=1
    
    
    # Restore radio device state (Bluetooth, WiFi, WWAN) from previous shutdown
    # on system startup: 0=disable, 1=enable.
    # Hint: the parameters DEVICES_TO_DISABLE/ENABLE_ON_STARTUP/SHUTDOWN below
    #   are ignored when this is enabled!
    RESTORE_DEVICE_STATE_ON_STARTUP=0
    
    
    # Radio devices to disable on startup: bluetooth, wifi, wwan.
    # Separate multiple devices with spaces.
    #DEVICES_TO_DISABLE_ON_STARTUP="bluetooth wifi wwan"
    
    
    # Radio devices to enable on startup: bluetooth, wifi, wwan.
    # Separate multiple devices with spaces.
    #DEVICES_TO_ENABLE_ON_STARTUP="wifi"
    
    
    # Radio devices to disable on shutdown: bluetooth, wifi, wwan
    # (workaround for devices that are blocking shutdown).
    #DEVICES_TO_DISABLE_ON_SHUTDOWN="bluetooth wifi wwan"
    
    
    # Radio devices to enable on shutdown: bluetooth, wifi, wwan
    # (to prevent other operating systems from missing radios).
    #DEVICES_TO_ENABLE_ON_SHUTDOWN="wwan"
    
    
    # Radio devices to enable on AC: bluetooth, wifi, wwan
    #DEVICES_TO_ENABLE_ON_AC="bluetooth wifi wwan"
    
    
    # Radio devices to disable on battery: bluetooth, wifi, wwan
    #DEVICES_TO_DISABLE_ON_BAT="bluetooth wifi wwan"
    
    
    # Radio devices to disable on battery when not in use (not connected):
    # bluetooth, wifi, wwan
    #DEVICES_TO_DISABLE_ON_BAT_NOT_IN_USE="bluetooth wifi wwan"
    
    
    # Battery charge thresholds (ThinkPad only, tp-smapi or acpi-call kernel module
    # required). Charging starts when the remaining capacity falls below the
    # START_CHARGE_THRESH value and stops when exceeding the STOP_CHARGE_THRESH value.
    # Main / Internal battery (values in %)
    #START_CHARGE_THRESH_BAT0=75
    #STOP_CHARGE_THRESH_BAT0=80
    # Ultrabay / Slice / Replaceable battery (values in %)
    #START_CHARGE_THRESH_BAT1=75
    #STOP_CHARGE_THRESH_BAT1=80
    
    
    # Restore charge thresholds when AC is unplugged: 0=disable, 1=enable
    #RESTORE_THRESHOLDS_ON_BAT=1
    
    
    # ------------------------------------------------------------------------------
    # tlp-rdw - Parameters for the radio device wizard
    # Possible devices: bluetooth, wifi, wwan
    
    
    # Hints:
    # - Parameters are disabled by default, remove the leading # to enable them.
    # - Separate multiple radio devices with spaces.
    
    
    # Radio devices to disable on connect.
    #DEVICES_TO_DISABLE_ON_LAN_CONNECT="wifi wwan"
    #DEVICES_TO_DISABLE_ON_WIFI_CONNECT="wwan"
    #DEVICES_TO_DISABLE_ON_WWAN_CONNECT="wifi"
    
    
    # Radio devices to enable on disconnect.
    #DEVICES_TO_ENABLE_ON_LAN_DISCONNECT="wifi wwan"
    #DEVICES_TO_ENABLE_ON_WIFI_DISCONNECT=""
    #DEVICES_TO_ENABLE_ON_WWAN_DISCONNECT=""
    
    
    # Radio devices to enable/disable when docked.
    #DEVICES_TO_ENABLE_ON_DOCK=""
    #DEVICES_TO_DISABLE_ON_DOCK=""
    
    
    # Radio devices to enable/disable when undocked.
    #DEVICES_TO_ENABLE_ON_UNDOCK="wifi"
    #DEVICES_TO_DISABLE_ON_UNDOCK=""

    Looks like this has done what I was trying to do.
    Now, the CPU is at ~1600 MHz with google chrome browsing 3 tabs (1 FB, 1 this forum, 1 microsoft outlook) + SMPlayer playing a video.
    If I unplug the AC and run lscpu with these same 3 tabs on chrome open + SMPlayer playing the same video, the CPU is at ~800MHz
    The cooling fan no longer spins up while on battery.

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