diff --git a/pytorch_lightning/models/trainer.py b/pytorch_lightning/models/trainer.py index ece5c7d4..88e36431 100644 --- a/pytorch_lightning/models/trainer.py +++ b/pytorch_lightning/models/trainer.py @@ -330,7 +330,7 @@ class Trainer(TrainerIO): world_size = self.nb_gpu_nodes * len(self.data_parallel_device_ids) # set up server using proc 0's ip address - ip = self.__get_root_node_ip(self.proc_rank, node_rank, self.nb_gpu_nodes, self.exp_save_path) + ip = self.__get_root_node_ip(self.proc_rank, self.nb_gpu_nodes, self.exp_save_path) dist.init_process_group("nccl", init_method=f'tcp://{ip}:12001', rank=self.proc_rank, world_size=world_size) print(f"GPU: {gpu_nb} - Rank: {self.proc_rank}") @@ -342,12 +342,12 @@ class Trainer(TrainerIO): # continue training routine self.__run_pretrain_routine(model) - def __get_root_node_ip(self, proc_rank, node_rank, nb_gpu_nodes, ip_file_dir): + def __get_root_node_ip(self, world_gpu_nb, nb_gpu_nodes, ip_file_dir): """ Resolves the ip address of proc 0. Proc 0 writes address to a file. Every other process waits until the ip is available before it starts - :param proc_rank: + :param world_gpu_nb: gpu number amongst all the world gpus :param nb_gpu_nodes: :param ip_file_dir: :return: @@ -356,10 +356,11 @@ class Trainer(TrainerIO): if nb_gpu_nodes == 1: return '127.0.0.1' - # on multi-node, every node rank > 0 waits until rank 0 + # the first gpu in the world becomes the host + # this is based on its global rank # saves the ip to disk ip_file = os.path.join(ip_file_dir, '.ip_meta') - if proc_rank == 0 and node_rank == 0: + if world_gpu_nb == 0: # get the proc 0 IP root_ip = subprocess.run(['hostname', '-I'], stdout=subprocess.PIPE).stdout.decode('utf-8') root_ip = root_ip.split(' ')[0]