Intel edison arduino analogRead()

If I use arduino uno or due, analogRead() function takes time about 0.1ms  ( and it is presented in arduino homepage )

But if i use Intel edison arduino, analogRead() function takes time about 20ms.......

I don't know what is the problem.

How can i solve this problem?

( digitalRead(), Serial.read() is okay.. but just analogRead() function is not working well.... )