test volatile ring

walltime: 42m29.711s
dataset: meta1
commit: 0cbcac70aa27d854266e8b68f4ab69817f569ec3 (no volatile and no atomic ring)
configuration: 4 x 7

walltime: 49m31.588s
dataset: meta1
commit: 0cbcac70aa27d854266e8b68f4ab69817f569ec3 (+ volatile and no atomic ring)
configuration: 4 x 7

walltime: 44m20s
dataset: meta1
commit: b6293d1aad7080488380fe763d7a270a89a64fe5 (atomic ring)
configuration: 4 x 7

Link: http://sc.tamu.edu/help/power/powerlearn/html/parallel-smpnw/sld017.htm
Link: https://github.com/GeneAssembly/biosal/issues/312
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>