Power saving mode linux

Introduction

There are many ways to reduce power consumption and extend battery life in Ubuntu. By default, most of these are not enabled because they are unreliable. With a little experimentation, you can get your power consumption down to a minimum.

PowerTOP Tunables

Before you start making any changes, it is a good idea to first get a base line for what your current power consumption is:

sudo aptitude install powertop sudo powertop

You must be running on battery power for powertop to get the machine’s current watt usage.

Then, One may tab over to the Tunables section to adjust the power management setting for each item in the list.

Measure temperature via lm-sensors

One helpful tool is to monitor the internal hardware temperatures via lm-sensors. For more on this, please see here. Please be mindful that taking temperature readings too often could also cause your temperature to increase. Hence, it’s best to use the longest time interval for your intended use.

Using less power with pm-powersave

The pm-utils package comes with scripts for managing low-power modes.

sudo aptitude install pm-utils

In order to enter low power mode, run this:

In order to leave low power mode, run this:

These commands will run the hooks in /etc/pm/power.d and /usr/lib/pm-utils/power.d, passing the argument true when entering power save and false when leaving.

When you run pm-powersave it combines the scripts in these two directories and executes them in sorted order. If both directories contain a script with the same name, the one in /etc/pm/power.d/ has a higher precedence and only this one will be executed.

Therefore to disable a script from /usr/lib/pm-utils/power.d/ simply create an empty file in /etc/pm/power.d/ with the same name and without the execute bit set.

An example power.d hook

# # A script to agressively toggle power management between high performance and very low power usage. # For more information on each of these options, see http://www.lesswatts.org # # To install: # # sudo install 99-savings /etc/pm/sleep.d # sudo install 99-savings /etc/pm/power.d # ## ## POWER SAVE OFF ## ac_power() ## ## DISK and FILESYSTEMS ## # Set the drive to mostly stay awake. Some may want to change -B 200 # to -B 255 to avoid accumulating Load_Cycle_Counts # -S 240 => put in standby after 20 minutes idle # -B 200 => do not permit spindown # -M => not supported by my drive hdparm -B 200 -S 240 /dev/sda # Remount ext3/4 filesystems so the journal commit only happens every 60 # seconds. By default this is 5 but, I prefer to reduce the disk # activity a bit. mount -o remount,commit=60,atime / # Turn off the laptop mode disk optimization echo 0 > /proc/sys/vm/laptop_mode # Set the SATA to max performance echo max_performance > /sys/class/scsi_host/host0/link_power_management_policy echo max_performance > /sys/class/scsi_host/host1/link_power_management_policy ## ## NETWORK ## # set the wifi to no power savings. iwconfig wlan0 power off ## ## CPU AND MEMORY ## # Set kernel dirty page value back to default echo 10 > /proc/sys/vm/dirty_ratio echo 5 > /proc/sys/vm/dirty_background_ratio # Only wakeup every 60 seconds to see if we need to write dirty pages # By default this is every 5 seconds but, I prefer 60 to reduce disk # activity. echo 6000 > /proc/sys/vm/dirty_writeback_centisecs # Make sure ondemand governor is set echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor ## ## SOUND AND VIDEO ## # Turn off sound card power savings echo 0 > /sys/module/snd_hda_intel/parameters/power_save # Enable the webcam driver modprobe uvcvideo > ## ## POWER SAVE ON ## battery_power() ## ## DISK and FILESYSTEMS ## # Set the disks to aggressively save power. # Some might find these settings too aggressive. If so, change # "-S 4" to something larger like -S 24 (two minutes) and -B 1 to -B 255. # -S 4 => put in standby after 20 seconds idle # -B 1 => highest degree of power savings # -M => not supported by my drive hdparm -B 1 -S 4 /dev/sda # Change ext3/ext4 filesystem settings to reduce disk activity. # noatime => disable updates to a file's access time when the file is read. # commit=600 => Change the commit times to 10 minutes. mount -o remount,noatime,commit=600 / # Set laptop disk write mode echo 5 > /proc/sys/vm/laptop_mode # Set SATA to minimum power echo min_power > /sys/class/scsi_host/host0/link_power_management_policy echo min_power > /sys/class/scsi_host/host1/link_power_management_policy ## ## NETWORK ## # set the wifi to power savings. iwconfig wlan0 power on ## ## CPU AND MEMORY ## # Make sure ondemand governor is set echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor # Reduce disk activity by waiting up to 10 minutes before doing writes echo 90 > /proc/sys/vm/dirty_ratio echo 1 > /proc/sys/vm/dirty_background_ratio echo 60000 > /proc/sys/vm/dirty_writeback_centisecs ## ## SOUND AND VIDEO ## # Set sound card power savings echo 10 > /sys/module/snd_hda_intel/parameters/power_save # Remove the webcam driver modprobe -r uvcvideo > ## ## APPLY SETTINGS ## case "$1" in false) ac_power ;; true) battery_power ;; esac

Debugging pm-powersave

sudo tail -f /var/log/pm-powersave.log & sudo pm-powersave true

Using less power with laptop-mode-tools

It is confusing: laptop_mode is a state that the kernel may be in, but laptop-mode-tools is a collection of scripts which attempt to reduce power consumption and allows you to tweak a number of power-related settings using a simple configuration file.

aptitude install laptop-mode-tools

If laptop-mode-tools is present, pm-utils will not manage disk settings but will assume that laptop-mode-tools is going to handle it (/usr/lib/pm-utils/power.d/95hdparm-apm).

However, pm-utils will not automatically start and stop laptop-mode-tools. To do so, we need to create a hook for pm-utils:

sudo touch /etc/pm/sleep.d/10-laptop-mode-tools sudo chmod a+x /etc/pm/sleep.d/10-laptop-mode-tools sudo gedit /etc/pm/sleep.d/10-laptop-mode-tools

case $1 in hibernate) /etc/init.d/laptop-mode stop ;; suspend) /etc/init.d/laptop-mode stop ;; thaw) /etc/init.d/laptop-mode start ;; resume) /etc/init.d/laptop-mode start ;; *) echo Something is not right. ;; esac

lm-profiler

Recent versions (1.11 and later) of laptop-mode-tools include a new tool lm-profiler. It will monitor your system’s disk usage and running network services and suggests to disable unneeded ones.

CPU governor

One may governor their CPU via the cpufreq-selector command, provided by the package gnome-applets. For example, if one had a dual core CPU, one could execute at a terminal:

sudo cpufreq-selector --cpu=0 --governor=powersave && sudo cpufreq-selector --cpu=1 --governor=powersave

This will change your CPU setting from ondemand, to powersave. Then, you could verify the CPU governor status by executing at a terminal:

This is provided by the package cpufrequtils.

If one wanted to have a lower CPU frequency persist through reboots, and choose which speed the CPU frequency runs on, one may edit the file /etc/init.d/cpufrequtils.

thermald

In Trusty+, one may utilize thermald. For more on this, please see here.

Using less resource intensive desktop environments

While Unity, GNOME3, and KDE provides a desktop experience that may be preferred by others, they can be more resource intensive. Hence, one may want to switch to Xubuntu, Lubuntu, or gnome-shell.

Dual and multi graphics card setups running hotter than Windows

Disable unused graphics cards

If one is not utilizing the discrete graphics card much, one would want to disable the card in the BIOS if an available option.

AMD FGLRX proprietary driver

Certain AMD graphics cards may have better heat profiles using the proprietary AMD driver fglrx, versus the default open source ones. The Ubuntu repositories offer various versions of the proprietary drivers noted here.

Radeon open source driver

echo low | sudo tee /sys/class/drm/card0/device/power_profile exit

One may verify the new profile via:

cat /sys/class/drm/card0/device/power_profile low

nouveau open source driver

For those with nvidia Optimus enabled graphics cards utilizing the nouveau driver, one may want to test Bumblebee to see if this would provide a desired improvement in the heat profile.

Increase fan speed

Dell Inspiron laptops

For Dell Inspiron laptops, one may use i8kmon to increase the fan speed. This utility is provided by the package i8kutils. For instructions on using this, please see the man page.

fancontrol

One may install the package fancontrol. Then execute at a terminal:

Power Saving Tweaks

General maintenance

Use a can of air to regularly blow out the dust that may accumulate in the computer exhaust area, which can cause incorrect heat flow, and air blockages. As well, do not obstruct the exhaust areas.

Related Links

PowerManagement/ReducedPower (последним исправлял пользователь 6 2014-11-08 16:47:59)

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Choose a power profile

You can manage power usage by choosing a Power Mode . There are three possible profiles:

• Balanced : Standard performance and power usage. This is the default setting.
• Power Saver : Reduced performance and power usage. This setting maximizes battery life. It may enable some power saving options, such as aggressively dimming the screen, and prevent those from being switched off.
• Performance : High performance and power usage. This mode will only be visible if it is supported by your computer. It will be selectable if your computer is running on AC power. If your device supports lap detection, you will not be able to select this option if the device is running on someone’s lap.

To choose a power profile:

1. Open the Activities overview and start typing Power .
2. Click Power to open the panel.
3. In the Power Mode section, choose one of the profiles.

More Information

See Also

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The material in this document is available under a free license, see Legal for details.
For information on contributing see the Ubuntu Documentation Team wiki page. To report errors in this documentation, file a bug.

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