For those who might wonder why, the quicksort splits the array into half and then repeats on the two halves. Thus the majority of spans are small and quickly p

For those who might wonder why, the quicksort splits the array into half and then repeats on the two halves. Thus the majority of spans are small and quickly processed, and hence the naive multithreaded version leads to lock contention as the threads fight to access the shared list of spans.