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Diffstat (limited to 'doc/HOWTO.txt')
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diff --git a/doc/HOWTO.txt b/doc/HOWTO.txt new file mode 100644 index 0000000..9f2d0f9 --- /dev/null +++ b/doc/HOWTO.txt @@ -0,0 +1,28 @@ +=== Simple user tips for improving power usage === +* Enforce turning of machines that are not used (e.g. company policy) +* Turn of unused hardware already in BIOS. +* Disable power hungry features. +* Enable CPU scaling if supported for ondemand CPU governor. DONT use powersave governor, typically uses more power than ondemand +(race to idle). +* Put network card to 100 mbit/10 mbit: +** 10 mbit: ethtool -s eth0 advertise 0x002 +** 100 mbit: ethtool -s eth0 advertise 0x008 +** Doesn't work for every card +* Put harddisk to spindown fast and full power saving: +** hdparm -S240 /dev/sda (20m idle to spindown) +** hdparm -B1 /dev/sda (Max powersave mode) +* Make sure writes to hd don't wake it up too quickly: +** Set flusing to once every hour +** echo "360000" > /proc/sys/vm/dirty_writeback_centisecs +** Enable laptop mode +** echo "1" > /proc/sys/vm/laptop_mode +* Screensaver needs to dpms off the screen, not just make colors black. To turn of monitor after 120s when X is running: +** xset dpms 0 0 120 + +=== Simple programmer tips for improving power usage === +* Wake up only when necessary +* No poll() calls +* If you wake up, do everything at once (race to idle) +* Use large buffers to avoid frequent disk access. Write one large block at a time +* Don't use [f]sync() if not necessary +* Group timers accross applications if possible (even systems) |