ColossalAI/colossalai/moe/experts.py

162 lines
6.1 KiB
Python

import math
from typing import Callable, Optional, Tuple
import torch
import torch.nn as nn
from colossalai.kernel.triton.llama_act_combine_kernel import HAS_TRITON
from colossalai.moe._operation import MoeInGradScaler, MoeOutGradScaler
from colossalai.moe.manager import MOE_MANAGER
from colossalai.moe.utils import get_activation
from colossalai.shardformer.layer.utils import Randomizer
from colossalai.tensor.moe_tensor.api import get_ep_rank, get_ep_size, set_moe_tensor_info
if HAS_TRITON:
from colossalai.kernel.triton.llama_act_combine_kernel import LlamaActCombine
class MLPExperts(nn.Module):
"""
SparseMLP is a multi-layer perceptron with sparse expert parallel layers.
Args:
num_experts (int): The number of experts
hidden_size (int): The hidden size of MLP
intermediate_size (int): The intermediate size of MLP
expert_parallel (str, optional): The parallelism of experts. Now we have None, EP and TP.
activation (optional): The activation function of MLP
drop_rate (float, optional): The drop rate of MLP
gated (bool, optional): Whether to use gated MLP
use_kernel (bool, optional): Whether to use kernel optimization
"""
def __init__(
self,
num_experts: int,
hidden_size: int,
intermediate_size: int,
expert_parallel: Optional[str] = None,
activation: Optional[Callable] = None,
drop_rate: Optional[float] = 0,
gated: Optional[bool] = False,
use_kernel: Optional[bool] = False,
):
super().__init__()
assert expert_parallel in ["EP", "TP", None]
self.expert_parallel = expert_parallel
self.num_total_experts = num_experts
self.gated = gated
self.use_kernel = use_kernel
self.hidden_size = hidden_size
self.intermediate_size = intermediate_size
# get expert parallel info
if expert_parallel is not None:
self.num_local_experts, self.moe_info = MOE_MANAGER.get_info(
num_experts, use_tp=True if expert_parallel == "TP" else False
)
# get settings for different parallel
self.ep_size = get_ep_size(self)
if expert_parallel == "TP":
intermediate_size = intermediate_size // self.ep_size
num_experts = self.num_total_experts
else:
num_experts = self.num_local_experts
else:
self.num_local_experts = self.num_total_experts
self.ep_size = 1
if gated:
self.wi_gate = nn.Parameter(
torch.empty(
num_experts, hidden_size, intermediate_size * 2 if activation == "swiglu" else intermediate_size
)
)
self.wi_up = nn.Parameter(torch.empty(num_experts, hidden_size, intermediate_size))
else:
self.wi = nn.Parameter(torch.empty(num_experts, hidden_size, intermediate_size))
self.wo = nn.Parameter(torch.empty(num_experts, intermediate_size, hidden_size))
self.act_name = activation
self.act = get_activation(activation)
self.drop = nn.Dropout(p=drop_rate)
if expert_parallel is not None:
for param in self.parameters():
set_moe_tensor_info(param, self.moe_info)
# init param
self.reset_parameters()
@torch.no_grad()
def reset_parameters(self):
# expert param should be different
if self.expert_parallel is not None:
seed_ctx = Randomizer(get_ep_rank(self)).fork_rng(enable_cpu=True)
else:
seed_ctx = Randomizer(42).fork_rng(enable_cpu=True)
with seed_ctx:
if self.gated:
torch.nn.init.normal_(self.wi_gate, std=math.sqrt(0.1 / self.hidden_size))
torch.nn.init.normal_(self.wi_up, std=math.sqrt(0.1 / self.hidden_size))
else:
torch.nn.init.normal_(self.wi, std=math.sqrt(0.1 / self.hidden_size))
torch.nn.init.normal_(self.wo, std=math.sqrt(0.1 / self.intermediate_size))
def forward(
self,
x: torch.Tensor,
param_slice: Tuple[slice] = (slice(None),),
use_sparse: bool = True,
) -> torch.Tensor:
"""
forward: hidden_size --> intermediate_size --> hidden_size
Args:
x (torch.Tensor): The input tensor of shape (num_groups, num_experts, capacity, hidden_size)
Returns:
torch.Tensor: The output tensor of shape (num_groups, num_experts, capacity, hidden_size)
"""
x = MoeInGradScaler.apply(x, self.ep_size)
e = x.size(1)
h = x.size(-1)
x = x.transpose(0, 1)
inshape = x.shape
x = x.reshape(e, -1, h)
if self.use_kernel and use_sparse:
seq_len = x.shape[1]
with torch.no_grad():
mask = x[:, :, 0] != 0.0
mask = torch.sum(mask, dim=-1)
x_list = []
for i in range(e):
x_list.append(x[i, : mask[i]])
x = x_list
if self.gated:
x_gate = [torch.mm(x[i], self.wi_gate[param_slice][i]) for i in range(e)]
x_up = [torch.mm(x[i], self.wi_up[param_slice][i]) for i in range(e)]
if self.use_kernel and HAS_TRITON and self.act_name == "swiglu":
x = [LlamaActCombine.apply(x_gate[i], x_up[i]) for i in range(e)]
else:
x = [self.act(x_gate[i]) * x_up[i] for i in range(e)]
else:
x = [torch.mm(x[i], self.wi[param_slice][i]) for i in range(e)]
x = [self.act(x[i]) for i in range(e)]
x = [self.drop(x[i]) for i in range(e)]
x = [torch.mm(x[i], self.wo[param_slice][i]) for i in range(e)]
if self.use_kernel and use_sparse:
for i in range(e):
x[i] = torch.nn.functional.pad(x[i], (0, 0, 0, seq_len - x[i].shape[0]), mode="constant", value=0)
x = torch.cat([x[i].unsqueeze(0) for i in range(e)], dim=0)
x = x.reshape(inshape)
x = x.transpose(0, 1).contiguous()
x = MoeOutGradScaler.apply(x, self.ep_size)
return x