InternLM/internlm/model/moe.py

132 lines
4.3 KiB
Python

import typing
import torch
from internlm.core.context import ParallelMode
from internlm.core.context import global_context as gpc
from internlm.moe.experts import Experts
from internlm.moe.sharded_moe import MOELayer, TopKGate
from internlm.utils.logger import get_logger
# Copyright (c) Microsoft Corporation.
# SPDX-License-Identifier: Apache-2.0
# DeepSpeed Team
# global llm logger
logger = get_logger(__file__)
def has_moe_layers(m):
has_moe = False
num_experts = 0
for _, module in m.named_modules():
if isinstance(module, MoE):
has_moe = True
num_experts = module.num_experts
break
return has_moe, num_experts
def is_moe_param(param: torch.Tensor) -> bool:
if hasattr(param, "allreduce") and not param.allreduce:
return True
return False
class MoE(torch.nn.Module):
"""Initialize an MoE layer.
Arguments:
hidden_size (int): the hidden dimension of the model, importantly this is also the input and output dimension.
expert (torch.nn.Module): the torch module that defines the expert (e.g., MLP, torch.linear).
num_experts (int, optional): default=1, the total number of experts per layer.
ep_size (int, optional): default=1, number of ranks in the expert parallel world or group.
k (int, optional): default=1, top-k gating value, only supports k=1 or k=2.
capacity_factor (float, optional): default=1.0, the capacity of the expert at training time.
eval_capacity_factor (float, optional): default=1.0, the capacity of the expert at eval time.
min_capacity (int, optional): default=4, the minimum capacity per expert regardless of the capacity_factor.
noisy_gate_policy (str, optional): default=None, noisy gate policy, valid options are 'Jitter', 'RSample'
or 'None'.
drop_tokens (bool, optional): default=True, whether to drop tokens - (setting to False is equivalent to
infinite capacity).
use_rts (bool, optional): default=True, whether to use Random Token Selection.
"""
def __init__(
self,
hidden_size,
expert,
num_experts=1,
ep_size=1,
k=1,
capacity_factor=1.0,
eval_capacity_factor=1.0,
min_capacity=4,
noisy_gate_policy: typing.Optional[str] = None,
drop_tokens: bool = True,
use_rts: bool = True,
using_default_moe: bool = True,
):
super().__init__()
assert (
num_experts % ep_size == 0
), f"Number of experts ({num_experts}) should be divisible by expert parallel size ({ep_size})"
self.ep_size = ep_size
self.num_experts = num_experts
self.num_local_experts = num_experts // self.ep_size
logger.info(
f"""Creating MoE layer with num_experts: {num_experts} | num_local_experts:
{self.num_local_experts} | expert_parallel_size: {self.ep_size}"""
)
assert noisy_gate_policy is None or noisy_gate_policy in ["None", "Jitter", "RSample"], (
"Unsupported noisy_gate_policy: " + noisy_gate_policy
)
experts = Experts(expert, self.num_local_experts)
if using_default_moe:
self.moe_layer = MOELayer(
TopKGate(
hidden_size,
num_experts,
k,
capacity_factor,
eval_capacity_factor,
min_capacity,
noisy_gate_policy,
drop_tokens,
use_rts,
),
experts,
gpc.get_group(ParallelMode.EXPERT),
self.ep_size,
self.num_local_experts,
)
def forward(self, hidden_states, used_token=None):
"""MoE forward
Arguments:
hidden_states (Tensor): input to the layer
used_token (Tensor, optional): default: None, mask only used tokens
Returns:
A tuple including output, gate loss, and expert count.
* output (Tensor): output of the model
* l_aux (Tensor): gate loss value
* exp_counts (int): expert count
"""
output = self.moe_layer(hidden_states, used_token)
return output, self.moe_layer.l_aux, self.moe_layer.exp_counts