As I understand, "wall time" measures simply time passed, from start to finish. This means that any thread that started before profiling began, and didn't finish during profiling, should have its total run time equal to profiling time. But that's not the case: when I profiled our application, I saw several threads that used about half total time. I used tracing for profiling and wall time measurement.
More info here: http://stackoverflow.com/questions/4946164/how-can-a-thread-use-less-than-100-wall-time
What does that mean? How can a thread use less than 100% wall time?