How could I find the critical functions when dual core cpu is fully loading?

It can see almost 100% CPU0 usage during the timeline 2.34s ~ 2.42s(in figure 1). How can we know which functions are executed in CPU0/ CPU1 @timeline 2.376s(in figure 2)?

The figure 3 is show the functions sheet @timeline 2.376s, but no more information about CPU.

Please let us know if you know how to check functions executed in CPU0/1. Thank you

Figure 1                                                                            

Figure 2.

Figure 3.