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project_6/ixformer_sdk/contrib/tgi/fused_moe.py

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import functools
import json
import os
from typing import Any, Dict, Optional, Tuple
from loguru import logger
import torch
import ixformer.inference.functions as ops
CHUNK_SIZE = int(os.getenv("VLLM_FUSED_MOE_CHUNK_SIZE", "65536"))
def fused_topk(
hidden_states: torch.Tensor,
gating_output: torch.Tensor,
topk: int,
renormalize: bool,
):
assert hidden_states.shape[0] == gating_output.shape[0], (
"Number of tokens mismatch")
M, _ = hidden_states.shape
topk_weights = torch.empty(M,
topk,
dtype=torch.float32,
device=hidden_states.device)
topk_ids = torch.empty(M,
topk,
dtype=torch.int32,
device=hidden_states.device)
token_expert_indicies = torch.empty(M,
topk,
dtype=torch.int32,
device=hidden_states.device)
ops.vllm_moe_topk_softmax(
topk_weights,
topk_ids,
token_expert_indicies,
gating_output.float(), # TODO(woosuk): Optimize this.
)
del token_expert_indicies # Not used. Will be used in the future.
if renormalize:
topk_weights = topk_weights / topk_weights.sum(dim=-1, keepdim=True)
return topk_weights, topk_ids
# This is used by the Deepseek-V2 model
def grouped_topk(hidden_states: torch.Tensor,
gating_output: torch.Tensor,
topk: int,
renormalize: bool,
num_expert_group: int = 0,
topk_group: int = 0):
assert hidden_states.shape[0] == gating_output.shape[0], (
"Number of tokens mismatch")
scores = torch.softmax(gating_output, dim=-1)
num_token = scores.shape[0]
group_scores = scores.view(num_token, num_expert_group,
-1).max(dim=-1).values # [n, n_group]
group_idx = torch.topk(group_scores, k=topk_group, dim=-1,
sorted=False)[1] # [n, top_k_group]
group_mask = torch.zeros_like(group_scores) # [n, n_group]
group_mask.scatter_(1, group_idx, 1) # [n, n_group]
score_mask = group_mask.unsqueeze(-1).expand(
num_token, num_expert_group,
scores.shape[-1] // num_expert_group).reshape(num_token, -1) # [n, e]
tmp_scores = scores.masked_fill(~score_mask.bool(), 0.0) # [n, e]
topk_weights, topk_ids = torch.topk(tmp_scores,
k=topk,
dim=-1,
sorted=False)
if renormalize:
topk_weights = topk_weights / topk_weights.sum(dim=-1, keepdim=True)
return topk_weights, topk_ids
def get_config_file_name(E: int, N: int, dtype: Optional[str]) -> str:
device_name = torch.cuda.get_device_name().replace(" ", "_")
dtype_selector = "" if not dtype else f",dtype={dtype}"
return f"E={E},N={N},device_name={device_name}{dtype_selector}.json"
@functools.lru_cache
def get_moe_configs(E: int, N: int,
dtype: Optional[str]) -> Optional[Dict[int, Any]]:
"""
Return optimized configurations for the fused MoE kernel.
The return value will be a dictionary that maps an irregular grid of
batch sizes to configurations of the fused_moe kernel. To evaluate the
kernel on a given batch size bs, the closest batch size in the grid should
be picked and the associated configuration chosen to invoke the kernel.
"""
# First look up if an optimized configuration is available in the configs
# directory
json_file_name = get_config_file_name(E, N, dtype)
config_file_path = os.path.join(
os.path.dirname(os.path.realpath(__file__)), "configs", json_file_name)
if os.path.exists(config_file_path):
with open(config_file_path) as f:
logger.info("Using configuration from %s for MoE layer.",
config_file_path)
# If a configuration has been found, return it
return {int(key): val for key, val in json.load(f).items()}
# If no optimized configuration is available, we will use the default
# configuration
return None
def get_default_config(
M: int,
E: int,
N: int,
K: int,
topk: int,
dtype: Optional[str],
) -> Dict[str, int]:
config = {
'BLOCK_SIZE_M': 64,
'BLOCK_SIZE_N': 64,
'BLOCK_SIZE_K': 32,
'GROUP_SIZE_M': 8
}
if M <= E:
config = {
'BLOCK_SIZE_M': 16,
'BLOCK_SIZE_N': 32,
'BLOCK_SIZE_K': 64,
'GROUP_SIZE_M': 1
}
numel = M * topk
if numel <= 64:
config['BLOCK_SIZE_M'] = 32
elif numel <= 1024:
config['BLOCK_SIZE_M'] = 64
else:
config['BLOCK_SIZE_M'] = 256
return config
def try_get_optimal_moe_config(
w1_shape: Tuple[int, ...],
w2_shape: Tuple[int, ...],
top_k: int,
dtype: Optional[str],
M: int,
override_config: Optional[Dict[str, Any]] = None,
):
if override_config:
config = override_config
else:
# First try to load optimal config from the file
E, _, N = w2_shape
configs = get_moe_configs(E, N, dtype)
if configs:
# If an optimal configuration map has been found, look up the
# optimal config
config = configs[min(configs.keys(), key=lambda x: abs(x - M))]
else:
# Else use the default config
config = get_default_config(M, E, N, w1_shape[2], top_k, dtype)
return config
def moe_align_block_size(
topk_ids: torch.Tensor, block_size: int,
num_experts: int) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
"""
Aligns the token distribution across experts to be compatible with block
size for matrix multiplication.
Parameters:
- topk_ids: A tensor of shape [total_tokens, top_k] representing the
top-k expert indices for each token.
- block_size: The block size used in block matrix multiplication.
- num_experts: The total number of experts.
Returns:
- sorted_token_ids: A tensor containing the sorted token indices according
to their allocated expert.
- expert_ids: A tensor indicating the assigned expert index for each block.
- num_tokens_post_padded: The total number of tokens after padding,
ensuring divisibility by block_size.
This function pads the number of tokens that each expert needs to process
so that it is divisible by block_size.
Padding ensures that during block matrix multiplication, the dimensions
align correctly.
Example:
Given topk_ids = [[2, 3, 4], [1, 2, 4], [1, 3, 4], [1, 2, 3]],
block_size = 4, and num_experts = 4:
- We initially have 12 tokens (after repeating 'top_k' times) and 4 experts,
with each expert needing to process 3 tokens.
- As block_size is 4, we pad 1 token for each expert.
- First, flatten topk_ids to [2, 3, 4, 1, 2, 4, 1, 3, 4, 1, 2, 3].
- Then append padding tokens [12, 12, 12, 12] for each block.
- After sorting by expert index, we obtain token_ids
[3, 6, 9, 12, 0, 4, 10, 12, 1, 7, 11, 12, 2, 5, 8, 12].
Tokens 12 are non-existent (padding) and are ignored in
the subsequent matrix multiplication.
- The padding ensures that the total number of tokens is now divisible
by block_size for proper block matrix operations.
"""
max_num_tokens_padded = topk_ids.numel() + num_experts * (block_size - 1)
sorted_ids = torch.empty((max_num_tokens_padded, ),
dtype=torch.int32,
device=topk_ids.device)
sorted_ids.fill_(topk_ids.numel())
# max_num_m_blocks = triton.cdiv(max_num_tokens_padded, block_size)
max_num_m_blocks = topk_ids.numel() + num_experts
expert_ids = torch.empty((max_num_m_blocks, ),
dtype=torch.int32,
device=topk_ids.device)
num_tokens_post_pad = torch.empty((1),
dtype=torch.int32,
device=topk_ids.device)
ops.vllm_moe_align_block_size(topk_ids, num_experts, block_size, sorted_ids,
expert_ids, num_tokens_post_pad)
return sorted_ids, expert_ids, num_tokens_post_pad
def invoke_fused_moe_kernel(A: torch.Tensor, B: torch.Tensor, C: torch.Tensor,
A_scale: Optional[torch.Tensor],
B_scale: Optional[torch.Tensor],
topk_weights: torch.Tensor, topk_ids: torch.Tensor,
sorted_token_ids: torch.Tensor,
expert_ids: torch.Tensor,
num_tokens_post_padded: torch.Tensor,
mul_routed_weight: bool, top_k: int,
config: Dict[str, Any], compute_type: torch.dtype,
use_fp8: bool) -> None:
ops.vllm_invoke_fused_moe_kernel(A, B, C, topk_weights, topk_ids,
sorted_token_ids,expert_ids, num_tokens_post_padded,
mul_routed_weight, top_k, config['BLOCK_SIZE_M'])
def fused_experts(hidden_states: torch.Tensor,
w1: torch.Tensor,
w2: torch.Tensor,
topk_weights: torch.Tensor,
topk_ids: torch.Tensor,
inplace: bool = False,
override_config: Optional[Dict[str, Any]] = None,
use_fp8: bool = False,
w1_scale: Optional[torch.Tensor] = None,
w2_scale: Optional[torch.Tensor] = None,
a1_scale: Optional[torch.Tensor] = None,
a2_scale: Optional[torch.Tensor] = None):
# Check constraints.
assert hidden_states.shape[1] == w1.shape[2], "Hidden size mismatch"
assert topk_weights.shape == topk_ids.shape, "topk shape mismatch"
assert hidden_states.is_contiguous(), "Hidden_states must be contiguous"
assert w1.is_contiguous(), "Expert weights1 must be contiguous"
assert w2.is_contiguous(), "Expert weights2 must be contiguous"
assert hidden_states.dtype in [
torch.float32, torch.float16, torch.bfloat16
]
num_tokens, _ = hidden_states.shape
E, N, _ = w1.shape
# We execute the fused_moe kernel in chunks to circumvent this issue:
# https://github.com/vllm-project/vllm/issues/5938
M = min(num_tokens, CHUNK_SIZE)
get_config_func = functools.partial(
try_get_optimal_moe_config,
w1.shape,
w2.shape,
topk_ids.shape[1],
"float8" if use_fp8 else None,
override_config=override_config,
)
config = get_config_func(M)
intermediate_cache1 = torch.empty((M, topk_ids.shape[1], N),
device=hidden_states.device,
dtype=hidden_states.dtype)
intermediate_cache2 = torch.empty((M * topk_ids.shape[1], N // 2),
device=hidden_states.device,
dtype=hidden_states.dtype)
intermediate_cache3 = torch.empty((M, topk_ids.shape[1], w2.shape[1]),
device=hidden_states.device,
dtype=hidden_states.dtype)
compute_type = (torch.bfloat16
if hidden_states.dtype == torch.bfloat16 else torch.float16)
if inplace:
out_hidden_states = hidden_states
else:
out_hidden_states = torch.empty_like(hidden_states)
for chunk in range((num_tokens // CHUNK_SIZE) + 1):
begin_chunk_idx, end_chunk_idx = (chunk * CHUNK_SIZE,
min((chunk + 1) * CHUNK_SIZE,
num_tokens))
curr_hidden_states = hidden_states[begin_chunk_idx:end_chunk_idx]
tokens_in_chunk, _ = curr_hidden_states.shape
if tokens_in_chunk == 0:
break
if tokens_in_chunk < CHUNK_SIZE and chunk > 0:
# Adjust the intermediate cache size and config for the last
# chunk. Note that in most cases we only have one chunk
# so the cache size and config are already set correctly and
# do not need to be adjusted.
intermediate_cache1 = intermediate_cache1[:tokens_in_chunk]
intermediate_cache2 = intermediate_cache2[:tokens_in_chunk]
intermediate_cache3 = intermediate_cache3[:tokens_in_chunk]
config = get_config_func(tokens_in_chunk)
curr_topk_ids = topk_ids[begin_chunk_idx:end_chunk_idx]
curr_topk_weights = topk_weights[begin_chunk_idx:end_chunk_idx]
sorted_token_ids, expert_ids, num_tokens_post_padded = (
moe_align_block_size(curr_topk_ids, config['BLOCK_SIZE_M'], E))
invoke_fused_moe_kernel(curr_hidden_states,
w1,
intermediate_cache1,
a1_scale,
w1_scale,
curr_topk_weights,
curr_topk_ids,
sorted_token_ids,
expert_ids,
num_tokens_post_padded,
False,
topk_ids.shape[1],
config,
compute_type=compute_type,
use_fp8=use_fp8)
ops.silu_and_mul(intermediate_cache1.view(-1, N), intermediate_cache2)
invoke_fused_moe_kernel(intermediate_cache2,
w2,
intermediate_cache3,
a2_scale,
w2_scale,
curr_topk_weights,
curr_topk_ids,
sorted_token_ids,
expert_ids,
num_tokens_post_padded,
True,
1,
config,
compute_type=compute_type,
use_fp8=use_fp8)
torch.sum(intermediate_cache3.view(*intermediate_cache3.shape),
dim=1,
out=out_hidden_states[begin_chunk_idx:end_chunk_idx])
return out_hidden_states
def fused_moe(
hidden_states: torch.Tensor,
w1: torch.Tensor,
w2: torch.Tensor,
gating_output: torch.Tensor,
topk: int,
renormalize: bool,
inplace: bool = False,
override_config: Optional[Dict[str, Any]] = None,
use_grouped_topk: bool = False,
num_expert_group: Optional[int] = None,
topk_group: Optional[int] = None,
use_fp8: bool = False,
w1_scale: Optional[torch.Tensor] = None,
w2_scale: Optional[torch.Tensor] = None,
a1_scale: Optional[torch.Tensor] = None,
a2_scale: Optional[torch.Tensor] = None,
) -> torch.Tensor:
"""
This function computes a Mixture of Experts (MoE) layer using two sets of
weights, w1 and w2, and top-k gating mechanism.
Parameters:
- hidden_states (torch.Tensor): The input tensor to the MoE layer.
- w1 (torch.Tensor): The first set of expert weights.
- w2 (torch.Tensor): The second set of expert weights.
- gating_output (torch.Tensor): The output of the gating operation
(before softmax).
- topk (int): The number of top-k experts to select.
- renormalize (bool): If True, renormalize the top-k weights to sum to 1.
- inplace (bool): If True, perform the operation in-place.
Defaults to False.
- override_config (Optional[Dict[str, Any]]): Optional override
for the kernel configuration.
- num_expert_group: Optional[int]: additional parameter for grouped_topk
- topk_group: Optional[int]: additional parameter for grouped_topk
- use_grouped_topk: If True, use grouped_topk instead of fused_topk
note: Deepseekv2 model uses grouped_topk
- use_fp8 (bool): If True, use fp8 arithmetic to compute the inner
products for w1 and w2. Defaults to False.
- w1_scale (Optional[torch.Tensor]): Optional scale to be used for
w1.
- w2_scale (Optional[torch.Tensor]): Optional scale to be used for
w2.
Returns:
- torch.Tensor: The output tensor after applying the MoE layer.
"""
# Check constraints.
assert gating_output.shape[1] == w1.shape[0], "Number of experts mismatch"
if use_grouped_topk:
assert num_expert_group is not None and topk_group is not None
topk_weights, topk_ids = grouped_topk(hidden_states, gating_output,
topk, renormalize,
num_expert_group, topk_group)
else:
topk_weights, topk_ids = fused_topk(hidden_states, gating_output, topk,
renormalize)
return fused_experts(hidden_states,
w1,
w2,
topk_weights,
topk_ids,
inplace=inplace,
override_config=override_config,
use_fp8=use_fp8,
w1_scale=w1_scale,
w2_scale=w2_scale,
a1_scale=a1_scale,
a2_scale=a2_scale)