Atomically report the percentage of wall time spent by each thread of this thread pool executing jobs since the last reset time, and set the reset time to now. The creation of the thread pool is considered a first reset time. This value is calculated as: ` sum(jobExecutionTime) 100% P_busy = ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ x ‐‐‐‐‐‐‐‐‐‐ timeSinceLastReset maxThreads ` Note that this percentage reflects the wall time spent per thread, and not CPU time per thread, or not even CPU time per processor. Also note that there is no guarantee that all threads are processed concurrently (e.g., the number of threads could be larger than the number of processors).