Difference between revisions of "Power saving"

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[[Category:Power management]]
#REDIRECT [[Power management]]
By default, audio power saving is turned off by most drivers. It can be enabled by setting the power_save parameter to a time (in seconds) to go in idle.
{{Note|Toggling the audio card's power state can cause a popping sound or noticeable latency on some broken hardware.}}
{{hc|/etc/modprobe.d/audio_power_save.conf|2=options snd_hda_intel power_save=1}}
{{hc|/etc/modprobe.d/audio_power_save.conf|2=options snd_ac97_codec power_save=1}}
==Disabling NMI watchdog==
The [[Wikipedia:Non-maskable interrupt|NMI]] watchdog is a debugging feature to catch hardware hangs and cause a kernel panic. On some systems it can generate a lot of interrupts, causing a noticeable increase in power usage.
{{hc|/etc/sysctl.d/disable_watchdog.conf|2=kernel.nmi_watchdog = 0}}
or add {{ic|nmi_watchdog}} as a [[kernel parameter]].
==Disabling Wake-on-LAN==
[[Wikipedia:Wake-on-LAN|Wake-on-LAN]] can be a useful feature, but if you're not making use of it then it's simply draining extra power waiting for a magic packet while in suspend.
Disabling for one interface:
{{hc|/etc/udev/rules.d/disable_wol_eth0.rules|2=ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth0" RUN+="/usr/sbin/ethtool -s eth0 wol d"}}
Disabling for all interfaces:
{{hc|/etc/udev/rules.d/disable_wol.rules|2=ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth*" RUN+="/usr/sbin/ethtool -s %k wol d"}}
==Wireless power saving==
Enabling for a specific interface:
{{hc|/etc/udev/rules.d/wlan0_power_save.rules|2=ACTION=="add", SUBSYSTEM=="net", KERNEL=="wlan0" RUN+="/usr/sbin/iw dev wlan0 set power_save on"}}
Enabling for all interfaces:
{{hc|/etc/udev/rules.d/wifi_power_save.rules|2=ACTION=="add", SUBSYSTEM=="net", KERNEL=="wlan*" RUN+="/usr/sbin/iw dev %k set power_save on"}}
=== Writeback Time ===
Increasing the VM dirty writeback time can help to aggregate I/O together - reducing disk writes, and decreasing power usage:
{{hc|/etc/sysctl.d/dirty_writeback.conf|2=vm.dirty_writeback_centisecs = 1500}}
To do the same for journal commits with ext4 and some other filesystems, use {{ic|commit=15}} as a parameter in [[fstab]] or with the {{ic|rootflags}} [[kernel parameter]].

Latest revision as of 12:30, 23 April 2015

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