15. The one or more non-transitory computer-readable media of claim 13 , wherein the suitability metric is based at least on one of a processing speed or I/O speed of a computer.
13. The one or more non-transitory computer-readable media of claim 12 , wherein the instructions further include instructions which, when executed by one or more hardware processors, cause determining whether a suitability metric evaluated over the sub-tree rooted at said each node exceeds a threshold value.