Daniel Schneller's Blog

The Battery Life Thread Following the iOS 4.2.1 release in the news and in forums I came across a discussion thread in Apple’s forums that is about the issue of some users having extremely poor battery life after the upgrade from iOS 3.2. I have not yet upgraded to 4.2 and I might in fact hold on to 3.2 for a little longer for other reasons, so I don’t know yet, if I will be affected the same way. There are some users claiming that this is what is to be expected now with multitasking and several apps taking up resources at the same time. Reading through these, I could not help to notice that there seems to be a fair bit of confusion and misinformation going on about how multitasking might contribute to this issue So from a developer point of view, let me just state a few things. Please note that the general tone of this is that the “Apple/iOS version” of multitasking is by no means comparable to what you know from Mac OS or Windows, so many analogies are just not correct.

Situation A few weeks ago I was performance tuning some code that ran quite regularly and took more time than it should, judging from the complexity of what is was doing. As usual, by merely looking that the code there was nothing blatantly, obviously, complete and ridiculously wrong - after all, it worked correctly. So I fired up trusty old JProfiler and had a look, just to find out that sometimes you can become just too lazy and reliant on libraries without realizing their characteristics deeply enough.