switch DMA worker threads to new threads API
switch DMA worker threads to new threads API

StanfordLegion/legion,chuckatkins/legion,chuckatkins/legion,sdalton1/legion,chuckatkins/legion,sdalton1/legion,chuckatkins/legion,sdalton1/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,StanfordLegion/legion,StanfordLegion/legion,sdalton1/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,StanfordLegion/legion,chuckatkins/legion,StanfordLegion/legion,StanfordLegion/legion