A Detailed Look At The ATI Linux Power Management

[Michael]

Why must it be a laptop?

To easily and accurately compare the power consumption.

[nanonyme]

To easily and accurately compare the power consumption.

So summa summarum this saves power on all platforms but actual savings are only easy to determine on laptops?

[bridgman]

Most power management implementations turn on more aggressive power saving functions when running in battery mode.

Desktop systems tend not to have battery mode - but IIRC all of the test results in this article were made when running on battery.

[nanonyme]

Desktop systems tend not to have battery mode - but IIRC all of the test results in this article were made when running on battery.

UPS counts as battery too there then, I think. Might also be possible to trick the system into thinking it's running on battery with some hackery. (virtual battery whose power level you could change should be interesting for power management benchmarking since then you could see if different power management levels are triggered on different battery levels)

[bridgman]

I was under the impression that UPS mode was more like a pending shutdown than a low power mode; or maybe this is something new that I hadn't heard about

Are you saying that "UPS mode" uses the same ACPI messages/whatever as an AC-to-battery transition in a laptop ? Is that separate from the "you might wanna be shutting down before I takes your power away" mode ?

[Louise]

Would it be possible to turn off the GPU completely, if you have a server you only access by SSH?

Or are on one that risk-averse?

[sylware]

It may be a good idea to see if the frequency governor system of linux could fit that power management system.

[Kalessian]

I'd say this is a good start, but I think that the real benefit will come with lowered voltages.

On a related note, is there any way at all to lower the GPU voltage through software in ubuntu? I have to use fglrx because I need ATI powerplay to keep my laptop from getting too hot under normal use. This forces me to use the old LTS ubuntu since my mobility x700 is no longer supported. I would love to upgrade to ubuntu 10.04.

[frej]

Better reporting/gathering of data

Make the graphs more... ehm interesting? We don't know if it's some extra wireless interrupt that decreases the FPS or the power settings.. so

Please add standard deviation of several runs....then it's likely that low FPS differences can be argues as equivalent. (Ie ignored).

Also, sometimes percent is a better scale than than FPS

[agd5f]

A couple quick notes regarding the current pm state:

- Voltage drop is already implemented for r1xx-r5xx chips in the new pm code
- Some additional asic features (like dynamic sclk and dynamic voltage where the asic scales the clocks/voltage rather than the driver doing it) are also already implemented in the driver for r1xx-r5xx asics. Whether or not these get enabled depends on the flags in the power state entry.
- Most r6xx/r7xx desktop cards have power saving modes