Propagate number of threads set to the optimizer and metric

Change-Id: Ia0218ed23d051328767a1cd4ac13b0b7f84b3b6e
Print ActiveOptimizer in registration metric

Change-Id: I1f5e62e463557ed72295b56745fa5d3c1063c3af
Set default number of levels to 1

Change-Id: I00ca8c0a431ced8bfd2cd4dbbe2b5ce8ab6702fb