Ubuntu
powernowd package

Use `conservative' governor instead of `ondemand' by default

Asked by Giuseppe Ciotta

Binary package hint: powernowd

from Documentation/cpu-freq/governors.txt:

"The CPUfreq governor "conservative", much like the "ondemand"
governor, sets the CPU depending on the current usage. It differs in
behaviour in that it gracefully increases and decreases the CPU speed
rather than jumping to max speed the moment there is any load on the
CPU. This behaviour more suitable in a battery powered environment."

As you may already know, `ondemand' behaves badly with batteries, potentially shortening theirs life. `conservatives' has been created for use in laptop environment, so why don't we use it? I use it all the time and have never experienced problems watching dvds or listening to music .

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This question was originally filed as bug #93404.

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Tabrez Mohammed (abuqutaita) said : 		#1

For a desktop machine, 'ondemand' is a better choice for the default governor since power usage usually isn't a concern. However, for laptops, 'conservative' is definitely the better governor, as you noted from the governors.txt document, and in the kernel config itself:

"If you have a desktop machine then you should really be considering the 'ondemand' governor instead, however if you are using a laptop, PDA or even an AMD64 based computer (due to the unacceptable step-by-step latency issues between the minimum and maximum frequency transitions in the CPU) you will probably want to use this governor."

Perhaps at setup, based on the hardware Ubuntu is being deployed on, the appropriate default governor should be selected (i.e. 'ondemand' for an Intel desktop, 'conservative' for everything else, including laptops and AMD desktops). This additional step *must* be fully automated, as we have to assume the user knows nothing (or cares little) about what governor is being used. Implementing this feature would increase the default battery time for laptop users, with no negative effects for desktop users.

Thoughts?

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Launchpad Janitor (janitor) said : 		#2

This question was expired because it remained in the 'Needs information' state without activity for the last 15 days.