Android devices not having JIT

Question

i was following the Performance Tips through the developer site. There mentions about android devices that don't have a JIT. But i searched for jit-less devices but could not find a broad list.

There are also huge differences between devices with and without a JIT: the best code for a device with a JIT is not always the best code for a device without.

or

On devices without a JIT, it is true that invoking methods via a variable with an exact type rather than an interface is slightly more efficient

Question is which devices dont have JIT, which devices have? And What is the optimal thinking while programming targeting mostly jit devices or it is not important?

Answer 1

Based on this article, JIT was added to the Dalvik VM in Android 2.2 (Froyo). This means Cupcake (1.5), Doughnut (1.6) and Eclair (2.1) don't have it. The Android Dashboard tells me that there are less than 2% of devices still in the wild without JIT.

Personally, I would not spend a minute thinking about devices without JIT; for one, those older devices would have smaller screens and fewer resources anyway, and aren't the target for my apps.

Answer 2

from command prompt go to android sdk platforrm-tools. From there

adb shell
dalvikvm -h

There at the bottom of the line there will be written Configured with: ..... jit.........