3 ms·

It's not useful if you're trying to measure the tradeoff, but it paints a clear picture for everyday use. If I'm just loading a web-page or playing a non-AAA g

by tux3 2y ago

It's not useful if you're trying to measure the tradeoff, but it paints a clear picture for everyday use. If I'm just loading a web-page or playing a non-AAA game like Terarria, I don't care whether I get 300fps or 200fps. I do care if my laptop has 4h of battery life with 6W consumed, or 8h and 3W. There's another demo if you click through on the Github repo where they start a make -j32 on the kernel in the background while Terraria is running, and (with low-power mode off) the FPS actually goes up significantly compared to EEVDF, which I would definitely not have expected from a small plug-in scheduler in userspace like this. I'd definitely like precise benchmarks, but for a proof of concept, I think it's a very interesting demo of what's possible.

viraptor 2y ago
Oh definitely, for a mostly idle system like using a browser it won't matter much and the energy savings are nice. But it would be great to know the trade-off because if you have 50% energy saving, but have to wait 2x the time, you're just wasting time.
- patshead 2y ago
  This can be such a complex problem. Maxing out 8 cores is rarely twice as fast as maxing out 4 cores, but it will likely make the CPU draw around twice as many watts. That makes it seem like it might be a better use of power to keep cores idle during a big compile job, but it also takes watts to drive the display and keep the backlight on. I can't imagine this would be easy to get right, and it is probably much harder to set a good default. Even so, the background compile job taking twice as long might not be a waste of time as long as I get to play Oxygen Not Included twice as long!
  - tux3 2y ago
    Just another way too much heat can threaten your ONI run :)
  - tadfisher 2y ago
    Race-to-idle is sometimes a goal, yeah; if you have some performance budget (say, a 16ms time slice), and a fixed workload, does it make sense to run resources at lower power and barely meet the budget, or to run everything at max power so they can spend the remainder at idle? The answer is different for many scenarios.

by tux3 2y ago

viraptor 2y ago

Oh definitely, for a mostly idle system like using a browser it won't matter much and the energy savings are nice. But it would be great to know the trade-off because if you have 50% energy saving, but have to wait 2x the time, you're just wasting time.

patshead 2y ago
This can be such a complex problem. Maxing out 8 cores is rarely twice as fast as maxing out 4 cores, but it will likely make the CPU draw around twice as many watts. That makes it seem like it might be a better use of power to keep cores idle during a big compile job, but it also takes watts to drive the display and keep the backlight on. I can't imagine this would be easy to get right, and it is probably much harder to set a good default. Even so, the background compile job taking twice as long might not be a waste of time as long as I get to play Oxygen Not Included twice as long!
- tux3 2y ago
  Just another way too much heat can threaten your ONI run :)
- tadfisher 2y ago
  Race-to-idle is sometimes a goal, yeah; if you have some performance budget (say, a 16ms time slice), and a fixed workload, does it make sense to run resources at lower power and barely meet the budget, or to run everything at max power so they can spend the remainder at idle? The answer is different for many scenarios.