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ColossalAI/colossalai/utils/checkpoint/utils.py

64 lines
2.1 KiB

import torch
import torch.distributed as dist
from colossalai.tensor import ColoTensor, ColoTensorSpec
from colossalai.tensor.distspec import _DistSpec, DistPlacementPattern
def robust_broadcast(tensor):
with torch.no_grad():
is_cpu_ten = tensor.device.type == 'cpu'
if is_cpu_ten:
b_data = tensor.cuda()
else:
b_data = tensor
dist.broadcast(b_data, 0)
if is_cpu_ten:
tensor.copy_(b_data)
def gather_tensor(colo_tensor: ColoTensor) -> None:
"""Make colo_tensor replicated when the rank is 0
"""
if not colo_tensor.is_replicate():
pg = colo_tensor.get_process_group()
# for the group which contains rank 0
if pg.dp_local_rank() == 0:
old_dist_spec = colo_tensor.dist_spec
colo_tensor.to_replicate_()
if dist.get_rank() != 0:
colo_tensor.set_dist_spec(old_dist_spec)
# synchronize all processes for unexpected problems
dist.barrier()
if dist.get_rank() == 0:
setattr(colo_tensor, 'save_ready', True) # set saving signature
def scatter_tensor(colo_tensor: ColoTensor, dist_spec: _DistSpec) -> None:
"""Reversal operation of `gather_tensor`.
"""
if dist_spec.placement == DistPlacementPattern.REPLICATE:
robust_broadcast(colo_tensor.data)
else:
global_size = colo_tensor.size_global()
if dist.get_rank() == 0:
entire_data = colo_tensor.data
else:
entire_data = torch.empty(global_size, device=colo_tensor.device)
robust_broadcast(entire_data)
if dist.get_rank() == 0:
colo_tensor.set_dist_spec(dist_spec)
else:
rep_tensor = ColoTensor(
entire_data, ColoTensorSpec(pg=colo_tensor.get_process_group(), compute_attr=colo_tensor.compute_spec))
rep_tensor.set_dist_spec(dist_spec)
with torch.no_grad():
colo_tensor.data.copy_(rep_tensor.data)
# synchronize all processes for unexpected problems
dist.barrier()