       |           |           |           |           |           |           |  Used       |
                           |  H     L  |  H     L  |  H     L  |  H     L  |  H     L  |  H     L  |             |
---------------------------+-----------+-----------+-----------+-----------+-----------+-----------+-------------+
                           |           |           |           |           |           |           |             |
PPL parallel sort          | 2.50  2.40| 1.34  1.16| 0.85  0.73| 0.70  0