FlameGraphWholeStrageCodeGen

Flame graphs of Spark to show the power of Whole stage code generation


I am trying Spark 2.0. I use the flame graph to profile the CPU cycle usage 
and find that whole stage code generations are widely used to optimize the performance.
From the physical plan, we can also see that the mark(*) indicates that part is optimized by the wholeStoageCodeGen.


![Flame graph](https://github.com/hustnn/TungstenSecret/blob/master/images/flame.png)

![physical plan](https://github.com/hustnn/TungstenSecret/blob/master/images/plan.png)