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from typing import Dict
import torch
import torch.distributed as dist
from colossalai.interface.optimizer import DistributedOptim
from colossalai.shardformer.layer._operation import _gather, _split
from colossalai.tensor.d_tensor import get_sharding_spec, is_distributed_tensor
class DistributedCAME(DistributedOptim):
"""Implements CAME algorithm.
This implementation is based on:
`CAME: Confidence-guided Adaptive Memory Efficient Optimization`
Args:
params (iterable): iterable of parameters to optimize or dicts defining
parameter groups
lr (float, optional): external learning rate (default: None)
eps (tuple[float, float]): regularization constants for square gradient
and instability respectively (default: (1e-30, 1e-16))
clip_threshold (float): threshold of root-mean-square of
final gradient update (default: 1.0)
betas (tuple[float, float, float]): coefficient used for computing running averages of
update, square gradient and instability (default: (0.9, 0.999, 0.9999)))
weight_decay (float, optional): weight decay (L2 penalty) (default: 0)
"""
def __init__(
self,
params,
lr=None,
eps=(1e-30, 1e-16),
clip_threshold=1.0,
betas=(0.9, 0.999, 0.9999),
weight_decay=0.0,
):
defaults = dict(
lr=lr,
eps=eps,
clip_threshold=clip_threshold,
betas=betas,
weight_decay=weight_decay,
)
self.tp_size = 1
self.tp_group = None
self.dp_size = 1
self.dp_group = None
self.shard_to_working_param = None # Dict{id:shape}, sample {id(param): torch.tensor}
self.use_zero = True
self.param_is_dtensor_dict = {} # {id(p): True/False}
self.grad_shape_dict = {} # {id(p): master param shape}
self.factored_dict = {} # {id(p): True/False}
self.use_first_moment_dict = {} # {id(p): True/False}
self.shard_spec_dict = {} # {id(p): ShardSpec}
super(DistributedCAME, self).__init__(params, defaults)
@property
def supports_memory_efficient_fp16(self):
return True
@property
def supports_flat_params(self):
return False
def setup_distributed(
self,
tp_group: dist.ProcessGroup = None,
dp_group: dist.ProcessGroup = None,
shard_to_working_param: Dict = {},
padding_map=None,
use_zero: bool = True,
) -> None:
"""
Inject features to the Optimizer
Args:
tp_group: The devices group for tensor parallel;
dp_group: The devices group for data parallel;
shard_to_working_param (Dict): ZeRO 2 feeds the optimizer a sharded param view as grads are sharded.
This maps from id(view) to working params used in forward & backward.
padding_map: Interface placeholder
use_zero: Whether or not to use zero;
"""
self.tp_group = tp_group # "Expected row process group"
self.dp_group = dp_group
if self.tp_group is not None:
self.tp_size = dist.get_world_size(self.tp_group)
if self.dp_group is not None:
self.dp_size = dist.get_world_size(self.dp_group)
self.use_zero = use_zero
self.shard_to_working_param = shard_to_working_param if shard_to_working_param is not None else {}
# grad is None, cause we dont setup now
for group in self.param_groups:
for p in group["params"]:
# w/o ZeRO: master param = working param
self.shard_to_working_param[id(p)] = self.shard_to_working_param.get(id(p), p)
self.param_is_dtensor_dict[id(p)] = is_distributed_tensor(self.shard_to_working_param[id(p)])
self.grad_shape_dict[id(p)] = self.shard_to_working_param[id(p)].shape
# Avoid row parallel lead H=1, then factored param is determined as not factored;
if self.param_is_dtensor_dict[id(p)]:
self.shard_spec_dict[id(p)] = get_sharding_spec(self.shard_to_working_param[id(p)])
if self.shard_spec_dict[id(p)].sharding_sequence[0] == "R":
self.factored_dict[id(p)] = True
elif self.shard_spec_dict[id(p)].sharding_sequence[-1] == "R":
self.factored_dict[id(p)] = True
else:
self.factored_dict[id(p)] = self._get_options(self.grad_shape_dict[id(p)])
else:
self.shard_spec_dict[id(p)] = None
self.factored_dict[id(p)] = self._get_options(self.grad_shape_dict[id(p)])
@staticmethod
def _get_options(param_shape):
factored = len(param_shape) >= 2
return factored
@staticmethod
def _rms(tensor, param_is_dtensor, use_zero, tp_size, dp_size, tp_group, dp_group):
tensor_sum = tensor.pow(2).sum()
num_of_element = tensor.numel()
if param_is_dtensor:
# reduce tensor_sum from tp_group
dist.all_reduce(tensor_sum, group=tp_group)
num_of_element = num_of_element * tp_size
if use_zero:
dist.all_reduce(tensor_sum, group=dp_group)
num_of_element = num_of_element * dp_size
rms = (tensor_sum / num_of_element).sqrt()
return rms
@staticmethod
def _approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col):
r_factor = (exp_avg_sq_row / exp_avg_sq_row.mean(dim=-1, keepdim=True)).rsqrt_().unsqueeze(-1)
c_factor = exp_avg_sq_col.unsqueeze(-2).rsqrt()
return torch.mul(r_factor, c_factor)
# approx_sq_grad for row parallel weight
@staticmethod
def _approx_sq_grad_row_parallel(exp_avg_sq_row, exp_avg_sq_col, sq_row_meam):
r_factor = (exp_avg_sq_row / sq_row_meam).rsqrt_().unsqueeze(-1)
c_factor = exp_avg_sq_col.unsqueeze(-2).rsqrt()
return torch.mul(r_factor, c_factor)
def _col_parallel_factor(self, update, grad, state_row, state_col, grad_shape, beta2t):
if grad_shape[0] % self.dp_size != 0:
# gather update[flatten] along dp group then reshape to [H, W/tp]
update = _gather(input_=update, dim=-1, process_group=self.dp_group)
update_reshape = update.view(-1, grad_shape[1])
# gather grad[flatten] along dp group then reshape to [H, W/tp]
grad = _gather(input_=grad, dim=-1, process_group=self.dp_group)
grad_reshape = grad.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H]
exp_avg_sq_col = state_col # [W/tp]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
update_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update_reshape.mul_(grad_reshape)
else:
update_reshape = update.view(-1, grad_shape[1])
grad_reshape = grad.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H]
exp_avg_sq_col = state_col # [W/tp]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
dist.all_reduce(exp_avg_sq_row, group=self.tp_group)
exp_avg_sq_row.div_(self.tp_size)
update_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update_reshape.mul_(grad_reshape)
if self.use_zero:
update = update_reshape.view(-1)
else:
update = update_reshape
return update
def _row_parallel_factor(self, update, grad, state_row, state_col, grad_shape, beta2t):
if grad_shape[0] % self.dp_size != 0:
# gather update[flatten] along dp group then reshape to [H/tp, W]
update = _gather(input_=update, dim=-1, process_group=self.dp_group)
# view update to origin[tp] shape
update_reshape = update.view(-1, grad_shape[1])
# gather grad[flatten] along dp group then reshape to [H/tp, W]
grad = _gather(input_=grad, dim=-1, process_group=self.dp_group)
grad_reshape = grad.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H]
exp_avg_sq_col = state_col # [W/tp]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
update_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update_reshape.mul_(grad_reshape)
if self.use_zero:
update = _split(input_=update_reshape.view(-1), dim=-1, process_group=self.dp_group)
else:
update = update_reshape
else:
update_reshape = update.view(-1, grad_shape[1])
grad_reshape = grad.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H]
exp_avg_sq_col = state_col # [W/tp]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
# gather row
exp_avg_sq_row_gather = _gather(input_=exp_avg_sq_row, dim=-1, process_group=self.tp_group)
sq_row_meam = exp_avg_sq_row_gather.mean(dim=-1, keepdim=True)
update_reshape = self._approx_sq_grad_row_parallel(exp_avg_sq_row, exp_avg_sq_col, sq_row_meam)
update_reshape.mul_(grad_reshape)
if self.use_zero:
update = update_reshape.view(-1)
else:
update = update_reshape
return update
def _base_factor(self, update, grad, state_row, state_col, grad_shape, beta2t):
if self.use_zero:
# only zero
# [30522, 128], [2, 128]
if grad_shape[0] % self.dp_size != 0:
# view update to origin shape update.view(grad_shape[0]//self.data_parallel_size , grad_shape[1])
# row mean no change
# col mean need reduce and div
# gather update[flatten] along dp group then reshape to [H, W]
update = _gather(input_=update, dim=-1, process_group=self.dp_group)
# view update to origin[tp] shape
update_reshape = update.view(-1, grad_shape[1])
# gather grad[flatten] along dp group then reshape to [H, W]
grad = _gather(input_=grad, dim=-1, process_group=self.dp_group)
grad_reshape = grad.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
update_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update_reshape.mul_(grad_reshape)
update = _split(input_=update_reshape.view(-1), dim=-1, process_group=self.dp_group)
else:
# no residual row
# view update to origin[tp] shape
update_reshape = update.view(-1, grad_shape[1]) # [H/dp, W]
grad_reshape = grad.view(-1, grad_shape[1]) # [H/dp, W]
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
exp_avg_sq_row.mul_(beta2t).add_(update_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(update_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
update_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update_reshape.mul_(grad_reshape)
update = update_reshape.view(-1)
else:
# # base factor; no tp, no dp
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
# Exponential average of row indexes
exp_avg_sq_row.mul_(beta2t).add_(update.mean(dim=-1), alpha=(1.0 - beta2t))
# Exponential average of columns indexes
exp_avg_sq_col.mul_(beta2t).add_(update.mean(dim=-2), alpha=(1.0 - beta2t))
# Approximation of exponential moving average of square of gradient
update = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
update.mul_(grad)
return update
# factor
def _base_res_factor(self, res, exp_avg, state_row, state_col, grad_shape, beta2t):
if self.use_zero:
# only zero
if grad_shape[0] % self.dp_size != 0:
# view res to origin shape res.view(grad_shape[0]//self.data_parallel_size , grad_shape[1])
# row mean no change
# col mean need reduce and div
# gather res[flatten] along dp group then reshape to [H, W]
res = _gather(input_=res, dim=-1, process_group=self.dp_group)
# view res to origin[tp] shape
res_reshape = res.view(-1, grad_shape[1])
# gather exp_avg[flatten] along dp group then reshape to [H, W]
exp_avg = _gather(input_=exp_avg, dim=-1, process_group=self.dp_group)
exp_avg_reshape = exp_avg.view(-1, grad_shape[1])
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
exp_avg_sq_row.mul_(beta2t).add_(res_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(res_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
res_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
res_reshape.mul_(exp_avg_reshape)
res = _split(input_=res_reshape.view(-1), dim=-1, process_group=self.dp_group)
else:
# no residual row
# view res to origin[tp] shape
res_reshape = res.view(-1, grad_shape[1]) # [H/dp, W]
exp_avg_reshape = exp_avg.view(-1, grad_shape[1]) # [H/dp, W]
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
exp_avg_sq_row.mul_(beta2t).add_(res_reshape.mean(dim=-1), alpha=(1.0 - beta2t))
exp_avg_sq_col.mul_(beta2t).add_(res_reshape.mean(dim=-2), alpha=(1.0 - beta2t))
# reduce col
dist.all_reduce(exp_avg_sq_col, group=self.tp_group)
exp_avg_sq_col.div_(self.tp_size)
res_reshape = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
res_reshape.mul_(exp_avg_reshape)
res = res_reshape.view(-1)
else:
# # base factor; no tp, no dp
exp_avg_sq_row = state_row # [H/dp]
exp_avg_sq_col = state_col # [W]
# Exponential average of row indexes
exp_avg_sq_row.mul_(beta2t).add_(res.mean(dim=-1), alpha=(1.0 - beta2t))
# Exponential average of columns indexes
exp_avg_sq_col.mul_(beta2t).add_(res.mean(dim=-2), alpha=(1.0 - beta2t))
# Approximation of exponential moving average of square of gradient
res = self._approx_sq_grad(exp_avg_sq_row, exp_avg_sq_col)
res.mul_(exp_avg)
return res
@torch.no_grad()
def step(self, closure=None):
"""Performs a single optimization step.
Args:
closure (callable, optional): A closure that reevaluates the model
and returns the loss.
"""
loss = None
if closure is not None:
loss = closure()
for group in self.param_groups:
for p in group["params"]:
if p.grad is None:
continue
grad = p.grad
if grad.is_sparse:
raise RuntimeError("CAME does not support sparse gradients.")
state = self.state[p]
# Under zero the grad_shape is the original grad that is flattened and then cut (only one dimension)
grad_shape = grad.shape
grad_shape = self.grad_shape_dict[id(p)]
param_is_dtensor = self.param_is_dtensor_dict[id(p)]
if param_is_dtensor:
grad_shape = self.shard_to_working_param.get(id(p)).shape # tp shape (2 dim)
factored = self.factored_dict[id(p)]
shard_spec = self.shard_spec_dict[id(p)]
# State Initialization
if len(state) == 0:
state["step"] = 0
state["exp_avg"] = torch.zeros_like(p)
if factored:
if param_is_dtensor:
if shard_spec.sharding_sequence[0] == "R": # Col Parallel
if grad_shape[0] % self.dp_size != 0:
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0], device=p.device, dtype=p.dtype
) # [H]
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0], device=p.device, dtype=p.dtype
) # [H]
else:
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=p.device, dtype=p.dtype
) # [H/dp]
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=p.device, dtype=p.dtype
) # [H/dp]
state["exp_avg_sq_col"] = torch.zeros(
grad_shape[1], device=p.device, dtype=p.dtype
) # [W/TP]
state["exp_avg_res_col"] = torch.zeros(
grad_shape[1], device=p.device, dtype=p.dtype
) # [W/TP]
if shard_spec.sharding_sequence[-1] == "R": # Row Parallel
# Row indivisible shape situation
if grad_shape[0] % self.dp_size != 0:
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0], device=p.device, dtype=p.dtype
) # [H/tp]
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0], device=p.device, dtype=p.dtype
) # [H/tp]
else:
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=p.device, dtype=p.dtype
) # [H/dp/tp]
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=p.device, dtype=p.dtype
) # [H/dp/tp]
state["exp_avg_sq_col"] = torch.zeros(
grad_shape[1], device=p.device, dtype=p.dtype
) # [W]
state["exp_avg_res_col"] = torch.zeros(
grad_shape[1], device=p.device, dtype=p.dtype
) # [W]
else:
if self.use_zero:
if grad_shape[0] % self.dp_size != 0:
# save all exp_avg_sq_row [H]
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0], device=grad.device, dtype=p.dtype
)
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0], device=grad.device, dtype=p.dtype
)
else:
# exp_avg_sq_row [H // dp]
state["exp_avg_sq_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=grad.device, dtype=p.dtype
)
state["exp_avg_res_row"] = torch.zeros(
grad_shape[0] // self.dp_size, device=grad.device, dtype=p.dtype
)
else:
# exp_avg_sq_row [H]
state["exp_avg_sq_row"] = torch.zeros(grad_shape[0], device=grad.device, dtype=p.dtype)
state["exp_avg_res_row"] = torch.zeros(grad_shape[0], device=grad.device, dtype=p.dtype)
# exp_avg_sq_col alaways [W]
state["exp_avg_sq_col"] = torch.zeros(grad_shape[1], device=grad.device, dtype=p.dtype)
state["exp_avg_res_col"] = torch.zeros(grad_shape[1], device=grad.device, dtype=p.dtype)
else:
state["exp_avg_sq"] = torch.zeros_like(p)
state["RMS"] = 0
else:
if factored:
state["exp_avg_sq_row"] = state["exp_avg_sq_row"]
state["exp_avg_sq_col"] = state["exp_avg_sq_col"]
state["exp_avg_res_row"] = state["exp_avg_sq_row"]
state["exp_avg_res_col"] = state["exp_avg_sq_col"]
else:
state["exp_avg_sq"] = state["exp_avg_sq"]
state["step"] += 1
update = (grad**2) + group["eps"][0]
if factored:
if param_is_dtensor:
# ==============================
# First Dim is R, Last Dim is S{} means split dim -1 --->
# Coloum Parallel ---> sq_row need Do (col) Reduce
# ==============================
if shard_spec.sharding_sequence[0] == "R":
update = self._col_parallel_factor(
update,
grad,
state["exp_avg_sq_row"],
state["exp_avg_sq_col"],
grad_shape,
group["betas"][1],
)
# ==============================
# Last Dim is R, First Dim is S{} means split dim 0 --->
# Row Parallel ---> sq_col need Do (row) Reduce
# ==============================
elif shard_spec.sharding_sequence[-1] == "R":
update = self._row_parallel_factor(
update,
grad,
state["exp_avg_sq_row"],
state["exp_avg_sq_col"],
grad_shape,
group["betas"][1],
)
else:
update = self._base_factor(
update,
grad,
state["exp_avg_sq_row"],
state["exp_avg_sq_col"],
grad_shape,
group["betas"][1],
)
else:
exp_avg_sq = state["exp_avg_sq"]
exp_avg_sq.mul_(group["betas"][1]).add_(update, alpha=(1.0 - group["betas"][1]))
update = exp_avg_sq.rsqrt().mul_(grad)
rms = self._rms(
update,
param_is_dtensor,
self.use_zero,
self.tp_size,
self.dp_size,
self.tp_group,
self.dp_group,
)
update.div_((rms / group["clip_threshold"]).clamp_(min=1.0))
exp_avg = state["exp_avg"]
exp_avg.mul_(group["betas"][0]).add_(update, alpha=1 - group["betas"][0])
# Confidence-guided strategy
# Calculation of instability
res = (update - exp_avg) ** 2 + group["eps"][1]
if factored:
if param_is_dtensor:
# ==============================
# First Dim is R, Last Dim is S{} means split dim -1 --->
# Coloum Parallel ---> sq_row need Do (col) Reduce
# ==============================
if shard_spec.sharding_sequence[0] == "R":
update = self._col_parallel_factor(
res,
exp_avg,
state["exp_avg_res_row"],
state["exp_avg_res_col"],
grad_shape,
group["betas"][2],
)
# ==============================
# Last Dim is R, First Dim is S{} means split dim 0 --->
# Row Parallel ---> sq_col need Do (row) Reduce
# ==============================
elif shard_spec.sharding_sequence[-1] == "R":
update = self._row_parallel_factor(
res,
exp_avg,
state["exp_avg_res_row"],
state["exp_avg_res_col"],
grad_shape,
group["betas"][2],
)
else:
update = self._base_res_factor(
res,
exp_avg,
state["exp_avg_res_row"],
state["exp_avg_res_col"],
grad_shape,
group["betas"][2],
)
else:
update = exp_avg
if group["weight_decay"] != 0:
p.add_(p, alpha=-group["weight_decay"] * group["lr"])
update.mul_(group["lr"])
p.add_(-update)
return loss