Snapshot boot - Linux/Android

Question

I am a newbie to Android. I am trying to boot my Android device within ~10seconds.

I have tried optimizing android space, like avoiding zygote class preloading, package scanner etc. I have also tried with some optimizations in u boot and kernel level. Now my boot up time is ~20 seconds.

By doing some research, I found that its really hard to get the boot time under ~10 seconds. Some sites say that snapshot booting is the only resort for getting this under 10 seconds. I understood the logic behind snapshot boot. But I don't know how to implement snapshot boot. Many sites describes about the method, but none is giving me a clear cut idea. None of the sites is describing about the steps I have to perform for getting a snapshot image and thus boot from it later.

Can anyone help me out with this. Can someone give me a clear cut idea on how to create a snapshot image and how to resume from the created image on next boot ?