Indeed, moving to multiple cores is about doing more work faster which has a direct impact on battery life. You'd have to measure whether this allows you to race-to-sleep faster or not which is a delicate balancing act.
It is telling that battery life is almost never mentioned or discussed in depth anywhere. What is the battery impact of React Native? Or of this solution?
It's a really nasty problem too because power usage isn't linear. Chips tend to have voltage steps[1] as they increase in frequency so if you can do something longer and at lower frequency it uses less power than the same workload at a higher frequency for shorter time.
Compound that with the fact that you really want to bring the whole SoC to a low power state and just keep the display lit since 90% of the time users aren't actually moving something.
Arm has tried to solve this with big.LITTLE[2] to mixed results. It turns out that it's hard to build a general purpose scheduler that's power aware much like it's hard to build a general purpose memory allocator that's fast in every case.
Battery life has been a major focus 2 or 3 iterations of Android ago.
Google released the tool they created in order to benchmark it (battery historian). btw, releasing the tool they created for a specific improvement is what they do each time they focus on improving one aspect of the platform, and that's an excellent practice.
Google probably cares to some extent about battery life. I doubt that the mobile team behind let's say Youtube cares, but the framework team does.
Third party devs tend to do not worry at all about battery life .. unless they use a really excessive amount of battery and are shamed for it
It is telling that battery life is almost never mentioned or discussed in depth anywhere. What is the battery impact of React Native? Or of this solution?