Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap arena mcentral mspan 8b (non empty) mspan 8b (empty) mspan 8b mspan 8b mspan 8b mspan 8b mspan 8b mspan 8b mcentral mspan 16b (non empty) mspan 16b (empty) mspan 16b mspan 16b mspan 16b mspan 16b mspan 16b mspan 16b mspan 8b mspan 16b mspan 16b Tiny allocation slot 12b 4b 10b 12b No free mspan 16b