This is one implementation of the threaded-quicksort that creates a thread tree, with each parent thread responsible for creation and closing of it's children threads.
The quicksort algorithm itself is not changed. If the length of the array to sort is big enough (defined > seg_size) then a thread is created to sort it, else it is sorted in the same thread.
Test was done with creating a randomized array, and sorting it 20 times to calculate the average. The times here in ms.
Test was done on xubuntu-xenial running on a i7 processor with turboboost disabled, and clock frequency locked. Hyperthreading was left on.
| Array Size | qsort | thsort | Ratio |
|---|---|---|---|
| 1000 | 137.3 | 129.05 | 1.06 |
| 20000 | 3536.3 | 1810.55 | 1.95 |
| 100000 | 20042.5 | 7598.3 | 2.64 |
| 500000 | 111958.1 | 38927.45 | 2.88 |
| 1000000 | 239363.1 | 76807.7 | 3.12 |