> modern systems are designed to have close integration between the platform and the OS to perform appropriate thermal management.
What does this mean in practice for a standard laptop?
I mean, every laptop supports the classic "turn up fans when CPU gets hot" and "throttle CPU if it gets very hot" - is that not sufficient to let the CPU operate as fast as the laptop's thermal design will permit?
Trivial example: you want to avoid the exterior of the laptop getting hot enough to be uncomfortable for the user. If you support adaptive policies, you can read the skin temperature sensor and then only throttle the CPU if that's above a certain temperature. If you want to get more fancy, you can make that temperature conditional on whether there's a dock attached or not (if the machine's sitting on the desk then the bottom temperature can go higher than it could otherwise).
More complex example: the wifi chipset also produces heat. The platform designer should take into account what the effect of CPU thermal output is on the wifi chipset, and expose that information in a way that the OS can make a decision about whether the appropriate response is to throttle the CPU or allow the wifi chipset to throttle itself. Making that decision is going to depend on the current workload, so you don't want to try to implement this in firmware.
If you don't support adaptive policies, then you just restrict the CPU such that even under worst case scenarios, the components can never exceed the desired temperature. Of course, this means that you're (generally) running slower than necessary.
no, unfortunately it's nowhere close to sufficient.
Power management on various chips is a complicated subject, and most modern laptops do a LOT of things to try to draw out battery life as long as possible.
If it helps, you can think of thermal management and battery management as directly related (that heat is coming from somewhere, and it's the battery in the laptop - the more heat, the more energy being consumed [or wasted].)
What does this mean in practice for a standard laptop?
I mean, every laptop supports the classic "turn up fans when CPU gets hot" and "throttle CPU if it gets very hot" - is that not sufficient to let the CPU operate as fast as the laptop's thermal design will permit?