radeontop is a small utility which allows one to monitor the utilization of
 Radeon GPUs starting from the R600 series and newer using undocumented
 performance counters in the hardware. The utility works with the free
 drivers.
 .
 It displays the utilization of the graphics pipe, event engine, vertex cache,
 vertex group and tesselator, texture addresser and cache, the shader units
 and more, both with a relative percent value as well as a colorful bar diagram.