If you have been following the adventures of our hero over the last couple of years, you might remember that we can’t really trust sampling profilers for Java, and it’s even worse for Java’s instrumentation-based profilers. For sampling profilers, the so-called observer effect gets in the way: when we profile a program, the profiling itself can change the program’s performance behavior. This means we can’t simply increase the sampling frequency to get a more accurate profile, because the samplin...