Spintronics has rapidly emerged as a highly pursued research area in solid-state physics and devices. In the next generation of spintronics, spin current is expected to play a big role because of its extreme energy efficiency. The recently invented spin Hall effect of semiconductor 2D electron gas and transition metals is an extremely efficient way to convert charge current to spin current. Using the spin Hall effect of tantalum, we have injected spin angular momentum to an adjacent ferromagnet to control its domain wall motion. We use this physics to clock nanomagnetic bits in nanomagnetic logic, which is a low power alternative to CMOS based computing. We experimentally demonstrate that spin Hall effect based clocking consumes a current 100 times lower than conventional magnetic field based clocking.