I’m using cocos2dx v3.4 and box2d.
I have only an android device to test my game and I observe a jerky motion sometimes and also a drop in fps. The fps ranges from 60-70. Is the jerky motion caused because of drop in fps?
Yes it may be, but note that the cocos fps is only an average over 1 second.
If you get some frames that take a long time to process then you will get jerky motion but it will not reflect in the fps because it is averaged.
There are good tools in the Android SDK to enable you to identify the problem.
How do I control the fps?
Is this only for Android or does this happen in ios and Windows phones as well?
You control fps by controlling how much processing you do each frame.
Try building a windows or OSX desktop version and then do some profiling…
Can you tell me how to do profiling on Windows desktop. I can run my game on Visual Studio.
Google is your friend.