Error with DistributedDataParallel

[blizda]

Hi, I trying to run informer training with DistributedDataParallel, and get error

-- Process 1 terminated with the following error:
Traceback (most recent call last):
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/multiprocessing/spawn.py", line 20, in _wrap
    fn(i, *args)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/test_ddp_vanila_torch.py", line 71, in demo_basic
    outputs = ddp_model(torch.randint(20000, (3, 5120)))
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/parallel/distributed.py", line 511, in forward
    output = self.module(*inputs[0], **kwargs[0])
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/linformer_pytorch/linformer_pytorch.py", line 364, in forward
    tensor = self.linformer(tensor, **kwargs)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/linformer_pytorch/linformer_pytorch.py", line 321, in forward
    tensor = checkpoint(layer, tensor)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/utils/checkpoint.py", line 163, in checkpoint
    return CheckpointFunction.apply(function, preserve, *args)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/utils/checkpoint.py", line 74, in forward
    outputs = run_function(*args)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/linformer_pytorch/linformer_pytorch.py", line 61, in forward
    tensor = tensor + self.fn(tensor, **kwargs)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/linformer_pytorch/linformer_pytorch.py", line 235, in forward
    head_outputs.append(checkpoint(head,Q,K,V))
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/utils/checkpoint.py", line 163, in checkpoint
    return CheckpointFunction.apply(function, preserve, *args)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/utils/checkpoint.py", line 74, in forward
    outputs = run_function(*args)
  File "/home/dbliznyuk/.conda/envs/test_crash/lib/python3.8/site-packages/torch/nn/modules/module.py", line 722, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/dbliznyuk/test_crash_skript/linformer-pytorch/linformer_pytorch/linformer_pytorch.py", line 162, in forward
    P_bar = Q/torch.sqrt(torch.tensor(self.dim).type(Q.type()))
RuntimeError: Expected all tensors to be on the same device, but found at least two devices, cuda:1 and cuda:0!

Seems like this error connected with parameter sharing

Code for reproducing

import os
import tempfile
import torch
import torch.distributed as dist
import torch.nn as nn
import torch.optim as optim
import torch.multiprocessing as mp
from linformer_pytorch import LinformerLM
from torch.nn.parallel import DistributedDataParallel as DDP

def setup(rank, world_size):
    os.environ['MASTER_ADDR'] = 'localhost'
    os.environ['MASTER_PORT'] = '12355'

    # initialize the process group
    dist.init_process_group("gloo", rank=rank, world_size=world_size)

def cleanup():
    dist.destroy_process_group()

def demo_basic(rank, world_size):
    print(f"Running basic DDP example on rank {rank}.")
    setup(rank, world_size)

    # create model and move it to GPU with id rank

    model = LinformerLM(
            num_tokens=30522,  # Number of tokens in the LM
            input_size=5120,  # Dimension 1 of the input
            channels=128,  # Dimension 2 of the input
            dim_d=None,
            # Overwrites the inner dim of the attention heads. If None, sticks with the recommended channels // nhead, as in the "Attention is all you need" paper
            dim_k=128,  # The second dimension of the P_bar matrix from the paper
            dim_ff=128,  # Dimension in the feed forward network
            dropout_ff=0.15,  # Dropout for feed forward network
            nhead=16,  # Number of attention heads
            depth=12,  # How many times to run the model
            dropout=0.1,  # How much dropout to apply to P_bar after softmax
            activation="gelu",
            # What activation to use. Currently, only gelu and relu supported, and only on ff network.
            checkpoint_level="C2",  # What checkpoint level to use. For more information, see below.
            parameter_sharing="none",  # What level of parameter sharing to use. For more information, see below.
            k_reduce_by_layer=0,
            # Going down `depth`, how much to reduce `dim_k` by, for the `E` and `F` matrices. Will have a minimum value of 1.
            full_attention=False,
            # Use full attention instead, for O(n^2) time and space complexity. Included here just for comparison
            include_ff=True,  # Whether or not to include the Feed Forward layer
            w_o_intermediate_dim=None,
            # If not None, have 2 w_o matrices, such that instead of `dim*nead,channels`, you have `dim*nhead,w_o_int`, and `w_o_int,channels`
            emb_dim=128,  # If you want the embedding dimension to be different than the channels for the Linformer
        ).to(rank)
    ddp_model = DDP(model, device_ids=[rank])

    loss_fn = nn.CrossEntropyLoss()
    optimizer = optim.SGD(ddp_model.parameters(), lr=0.001)

    optimizer.zero_grad()
    outputs = ddp_model(torch.randint(20000, (3, 5120)))
    labels = torch.randint(20000, (3, 5120)).to(rank)
    loss_mx = labels != -100
    output = outputs[loss_mx].view(-1, 30522)
    labels = labels[loss_mx].view(-1)
    loss_fn(output, labels).backward()
    optimizer.step()

    cleanup()

def run_demo(demo_fn, world_size):
    mp.spawn(demo_fn,
             args=(world_size,),
             nprocs=world_size,
             join=True)

if __name__ == "__main__":
    run_demo(demo_basic, 2)

Also, with DataParallel training going normal

[tatp22]

Hey @blizda!

It should be fixed now. It was a simple 1 line change from

P_bar = Q/torch.sqrt(torch.tensor(self.dim).type(Q.type()))

to

P_bar = Q/torch.sqrt(torch.tensor(self.dim).type(Q.type())).to(Q.device)

Check it out with the latest commit or by downloading 0.19.3 from pip

[blizda]

Yes, this fix work, thanks