Linked by Hadrien Grasland on Fri 15th Apr 2011 10:24 UTC
OSNews, Generic OSes Ever since iPhoneOS (now iOS) has been released, there's an old fight going on about how multitasking should work on personal computers, and more specially what should happen to applications which are put in the background. Some advocate that they should be dipped in virtual liquid nitrogen and stop doing anything, like on iOS, which others advocate that they should continue to run in the background, like on desktop OSs. What about putting a little more flexibility in there?
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Multitasking <> Inefficient CPU utilization
by Alfman on Sat 16th Apr 2011 08:30 UTC
Alfman
Member since:
2011-01-28

Can someone explain to me why people believe that multitasking is inherently causing so much excess battery drain?

Sure, background apps _can_ drain the batter, but there's absolutely no reason they need to. Even with a persistent idle connection.

As long as they are event oriented or blocked, then the operating system will never wake them up until data is ready. So the VOIP client in the background should register at 0% cpu when connected but idle.


It sounds many of the posts are arguing that running two or three (active) tasks simultaneously consumes more battery current. While inherently true at any moment in time, it's not clear to me that the total battery draw after performing all three tasks in parallel is any worse than in series.


Keep in mind that CPUs are most efficient at full utilization. In other words, running the cpu at 100% for one minute is more efficient than running the cpu at 10% for ten minutes. Which, in turn, is more efficient than 1% for 100 minutes, etc.

Also, in series, the screen/wifi might need to be powered 3x as long than if the tasks could be done in parallel.

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