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ColossalAI/tests/test_zero/test_low_level/test_zero_ckpt.py

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3.2 KiB

import copy
import pytest
import torch
import torch.nn as nn
from torch.nn.parallel import DistributedDataParallel as DDP
from torch.testing import assert_close
import colossalai
from colossalai.testing import rerun_if_address_is_in_use, spawn
from colossalai.testing.random import seed_all
from colossalai.zero import LowLevelZeroOptimizer
class MlpModel(nn.Module):
def __init__(self):
super(MlpModel, self).__init__()
self.linear1 = nn.Linear(12, 24)
self.linear2 = nn.Linear(24, 12)
def forward(self, x):
x = self.linear1(x)
x = self.linear2(x)
return x
def loose_close(a, b, dtype: torch.dtype = torch.float32):
rtol = None
atol = None
if dtype is torch.float16:
rtol = 5e-2
atol = 5e-4
elif dtype is torch.bfloat16:
rtol = 4e-3
atol = 4e-3
a = a.detach().to(dtype)
b = b.detach().to(dtype).to(a.device)
assert_close(a, b, rtol=rtol, atol=atol)
def exam_zero_1_torch_ddp_ckpt():
"""
We examine the state_dict of zero and DDP.
Moreover, we examine the zero's loading checkpoint of a torch ckpt.
"""
local_rank = torch.distributed.get_rank()
seed_all(1453)
# create models
torch_model = MlpModel().cuda()
zero_model = copy.deepcopy(torch_model)
torch_model = DDP(torch_model.cuda(), static_graph=True).cuda()
# create optimizer
zero_optimizer = torch.optim.Adam(zero_model.parameters(), lr=1)
# we only test stage 1 here
# the state dicts of stage 1 and stage 2 are the same
zero_optimizer = LowLevelZeroOptimizer(
zero_optimizer, overlap_communication=True, initial_scale=1, reduce_bucket_size=262144
)
torch_optimizer = torch.optim.Adam(torch_model.parameters(), lr=1)
seed_all(1453 + local_rank)
# create
input_data = torch.rand(4, 12).cuda()
# forward
zero_output = zero_model(input_data)
torch_output = torch_model(input_data)
# backward
zero_optimizer.backward(zero_output.mean().float())
torch_output.mean().backward()
# step
zero_optimizer.step()
torch_optimizer.step()
torch_state_dict = torch_optimizer.state_dict()
zero_state_dict = zero_optimizer.state_dict()
# examine the original state dict
for torch_state, zero_state in zip(torch_state_dict["state"].values(), zero_state_dict["state"].values()):
for t_v, z_v in zip(torch_state.values(), zero_state.values()):
loose_close(t_v, z_v)
# empty the optimzer state
zero_optimizer.optim.state = []
# zero load a torch checkpoint
zero_optimizer.load_state_dict(copy.deepcopy(torch_state_dict))
zero_state_dict = zero_optimizer.state_dict()
# examine the loaded state dict
for torch_state, zero_state in zip(torch_state_dict["state"].values(), zero_state_dict["state"].values()):
for t_v, z_v in zip(torch_state.values(), zero_state.values()):
loose_close(t_v, z_v)
def run_dist(rank, world_size, port):
colossalai.launch(rank=rank, world_size=world_size, port=port, host="localhost")
exam_zero_1_torch_ddp_ckpt()
@pytest.mark.dist
@rerun_if_address_is_in_use()
def test_zero_ckpt():
spawn(run_dist, 2)
if __name__ == "__main__":
test_zero_ckpt()