ondemand vs conservative

Siegfried-Angel Gevatter Pujals siegfried at gevatter.com
Wed Sep 29 20:54:15 UTC 2010


Google gives me this:

"The ondemand (available since 2.6.10) and conservative (since 2.6.12)
are governors based on in kernel implementations of CPU scaling
algorithms: they scale the CPU frequencies according to the needs
(like does the userspace frequency scaling daemons, but in kernel).
They differs in the way they scale up and down. The ondemand governor
switches to the highest frequency immediately when there is load,
while the conservative governor increases frequency step by step.
Likewise they behave the other way round for stepping down frequency
when the CPU is idle. The conservative governor is good for battery
powered environments on AMD64 (but may not work on older ThinkPads
like the T21). Ondemand may not work on older laptops without Enhanced
SpeedStep due to latency reasons. Anyway, for recent enough Intel CPU,
ondemand is the one recommended for power efficiency (over userspace,
and even over "powersave") by the Intel's kernel developer Arjan van
de Ven"

Siegfried-Angel Gevatter Pujals (RainCT)
Free Software Developer       363DEAE3

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