Allow ThreadPool to run jobs in both modes, and improve scheduling
#1404
| Job | Run time |
|---|---|
| 9m 40s | |
| 9m 25s | |
| 27s | |
| 2m 49s | |
| 37s | |
| 2m 44s | |
| 1m 27s | |
| 3m 0s | |
| 9m 44s | |
| 3m 23s | |
| 9m 41s | |
| 9m 18s | |
| 1s | |
| 1s | |
| 1s | |
| 1s | |
| 1s | |
| 1h 2m 20s |