1. Move the test_matrix, volume name, and size to module-level variables
so they can be accessed externally if this is imported.
2. Separate the volume creation and volume cleanup into functions.
3. Separate the individual benchmark runs into a function.
This should enable easier calling of the various subcomponents
externally, e.g. for external benchmark scripts.
Joshua M. Boniface
ea7a4b2b85