legion_prof: use binary search for more efficient zoom
legion_prof: use binary search for more efficient zoom

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