MPU9150 (JEFF LIB) + FIFO_OVERFLOW INTERRUPT + SERIAL PRINT
When I've gotten into a bind with data being generated faster than I can dump it, or the process cannot tolerate the printing delays, I've made a memory buffer to store as much raw data as I can and print it after the test-run. If you're not using a debugger (which can print memory contents), you'll still need to have serial print code in your sketch but it can execute after the you run the code under test. Store the minimum size raw data (to maximize the amount you can store) and do the formatting on your PC. 
If you need to be able see what happened prior to an unusual event your code can detect, use a ring buffer (FIFO) in memory and let it wrap around (don't even bother to detect wrap-around). As soon as your code detects the event, print the ring-buffer contents. 
It's not continuous capture but often, it's enough.