from typing import List, Optional, Tuple
import torch
from transformers.modeling_outputs import BaseModelOutputWithPast
from transformers.models.llama.modeling_llama import LlamaAttention, LlamaDecoderLayer, LlamaModel, LlamaRMSNorm
from colossalai.inference.tensor_parallel.batch_infer_state import BatchInferState
from colossalai.kernel.triton import (
copy_kv_cache_to_dest,
llama_context_attn_fwd,
rotary_embedding_fwd,
token_attention_fwd,
)
try:
from vllm import layernorm_ops, pos_encoding_ops
rms_norm = layernorm_ops.rms_norm
rotary_embedding_neox = pos_encoding_ops.rotary_embedding_neox
HAS_VLLM_KERNERL = True
except:
print("fall back to original rotary_embedding_neox of huggingface")
print("install vllm from https://github.com/vllm-project/vllm to accelerate your inference")
print(
"if falied to install vllm, please use this branch to install: https://github.com/tiandiao123/vllm/tree/setup_branch"
)
HAS_VLLM_KERNERL = False
def rotate_half(x):
"""Rotates half the hidden dims of the input."""
x1 = x[..., : x.shape[-1] // 2]
x2 = x[..., x.shape[-1] // 2 :]
return torch.cat((-x2, x1), dim=-1)
def apply_rotary_pos_emb(q, k, cos, sin, position_ids):
# The first two dimensions of cos and sin are always 1, so we can `squeeze` them.
cos = cos.squeeze(1).squeeze(0) # [seq_len, dim]
sin = sin.squeeze(1).squeeze(0) # [seq_len, dim]
cos = cos[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim]
sin = sin[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim]
q_embed = (q * cos) + (rotate_half(q) * sin)
k_embed = (k * cos) + (rotate_half(k) * sin)
return q_embed, k_embed
def _copy_kv_to_mem_cache(layer_id, key_buffer, value_buffer, context_mem_index, mem_manager):
copy_kv_cache_to_dest(key_buffer, context_mem_index, mem_manager.key_buffer[layer_id])
copy_kv_cache_to_dest(value_buffer, context_mem_index, mem_manager.value_buffer[layer_id])
return
class LlamaInferenceForwards:
"""
This class holds forwards for llama inference.
We intend to replace the forward methods for LlamaModel, LlamaDecoderLayer, and LlamaAttention for LlamaForCausalLM.
"""
@staticmethod
def llama_model_forward(
self: LlamaModel,
input_ids: torch.LongTensor = None,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[List[torch.FloatTensor]] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
):
batch_size = input_ids.shape[0] # input_ids.shape[0]
infer_state = self.infer_state
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
# retrieve input_ids and inputs_embeds
if input_ids is not None and inputs_embeds is not None:
raise ValueError("You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time")
elif input_ids is not None:
batch_size, seq_length = input_ids.shape
elif inputs_embeds is not None:
batch_size, seq_length, _ = inputs_embeds.shape
else:
raise ValueError("You have to specify either decoder_input_ids or decoder_inputs_embeds")
seq_length_with_past = seq_length
past_key_values_length = 0
if past_key_values is not None:
# NOT READY FOR PRIME TIME
# dummy but work, revise it
past_key_values_length = infer_state.cache_manager.past_key_values_length
# past_key_values_length = past_key_values[0][0].shape[2]
seq_length_with_past = seq_length_with_past + past_key_values_length
# NOTE: differentiate with prefill stage
# block_loc require different value-assigning method for two different stage
if use_cache and seq_length != 1:
# NOTE assume prefill stage
# allocate memory block
infer_state.is_context_stage = True # set prefill stage, notify attention layer
infer_state.context_mem_index = infer_state.cache_manager.alloc(infer_state.total_token_num)
infer_state.init_block_loc(
infer_state.block_loc, infer_state.seq_len, seq_length, infer_state.context_mem_index
)
else:
infer_state.is_context_stage = False
alloc_mem = infer_state.cache_manager.alloc_contiguous(batch_size)
if alloc_mem is not None:
infer_state.decode_is_contiguous = True
infer_state.decode_mem_index = alloc_mem[0]
infer_state.decode_mem_start = alloc_mem[1]
infer_state.decode_mem_end = alloc_mem[2]
infer_state.block_loc[:, seq_length_with_past - 1] = infer_state.decode_mem_index
else:
print(f" *** Encountered allocation non-contiguous")
print(
f" infer_state.cache_manager.past_key_values_length: {infer_state.cache_manager.past_key_values_length}"
)
infer_state.decode_is_contiguous = False
alloc_mem = infer_state.cache_manager.alloc(batch_size)
infer_state.decode_mem_index = alloc_mem
# infer_state.decode_key_buffer = torch.empty((batch_size, self.tp_head_num_, self.head_dim_), dtype=torch.float16, device="cuda")
# infer_state.decode_value_buffer = torch.empty((batch_size, self.tp_head_num_, self.head_dim_), dtype=torch.float16, device="cuda")
infer_state.block_loc[:, seq_length_with_past - 1] = infer_state.decode_mem_index
if position_ids is None:
device = input_ids.device if input_ids is not None else inputs_embeds.device
position_ids = torch.arange(
past_key_values_length, seq_length + past_key_values_length, dtype=torch.long, device=device
)
position_ids = position_ids.unsqueeze(0).view(-1, seq_length)
else:
position_ids = position_ids.view(-1, seq_length).long()
if infer_state.is_context_stage:
infer_state.position_cos = torch.index_select(self._cos_cached, 0, position_ids.view(-1)).view(
position_ids.view(-1).shape[0], -1
)
infer_state.position_sin = torch.index_select(self._sin_cached, 0, position_ids.view(-1)).view(
position_ids.view(-1).shape[0], -1
)
else:
seq_len = infer_state.seq_len
infer_state.position_cos = torch.index_select(self._cos_cached, 0, seq_len - 1).view(seq_len.shape[0], -1)
infer_state.position_sin = torch.index_select(self._sin_cached, 0, seq_len - 1).view(seq_len.shape[0], -1)
if inputs_embeds is None:
inputs_embeds = self.embed_tokens(input_ids)
# embed positions
if attention_mask is None:
attention_mask = torch.ones(
(batch_size, seq_length_with_past), dtype=torch.bool, device=inputs_embeds.device
)
attention_mask = self._prepare_decoder_attention_mask(
attention_mask, (batch_size, seq_length), inputs_embeds, past_key_values_length
)
hidden_states = inputs_embeds
# decoder layers
all_hidden_states = () if output_hidden_states else None
all_self_attns = () if output_attentions else None
next_decoder_cache = () if use_cache else None
infer_state.decode_layer_id = 0
for idx, decoder_layer in enumerate(self.layers):
past_key_value = past_key_values[idx] if past_key_values is not None else None
# NOTE: modify here for passing args to decoder layer
layer_outputs = decoder_layer(
hidden_states,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_value=past_key_value,
output_attentions=output_attentions,
use_cache=use_cache,
infer_state=infer_state,
)
infer_state.decode_layer_id += 1
hidden_states = layer_outputs[0]
if use_cache:
next_decoder_cache += (layer_outputs[2 if output_attentions else 1],)
hidden_states = self.norm(hidden_states)
next_cache = next_decoder_cache if use_cache else None
# update indices
# infer_state.block_loc[:, infer_state.max_len_in_batch-1] = infer_state.total_token_num + torch.arange(0, batch_size, dtype=torch.int32, device="cuda")
infer_state.start_loc = infer_state.start_loc + torch.arange(0, batch_size, dtype=torch.int32, device="cuda")
infer_state.seq_len += 1
if not return_dict:
return tuple(v for v in [hidden_states, next_cache, all_hidden_states, all_self_attns] if v is not None)
return BaseModelOutputWithPast(
last_hidden_state=hidden_states,
past_key_values=next_cache,
hidden_states=all_hidden_states,
attentions=all_self_attns,
)
@staticmethod
def llama_decoder_layer_forward(
self: LlamaDecoderLayer,
hidden_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
output_attentions: Optional[bool] = False,
use_cache: Optional[bool] = False,
infer_state: Optional[BatchInferState] = None,
) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
# Self Attention
hidden_states, self_attn_weights, present_key_value = self.self_attn(
hidden_states=hidden_states,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_value=past_key_value,
output_attentions=output_attentions,
use_cache=use_cache,
infer_state=infer_state,
)
hidden_states = residual + hidden_states
# Fully Connected
residual = hidden_states
hidden_states = self.post_attention_layernorm(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states
outputs = (hidden_states,)
if output_attentions:
outputs += (self_attn_weights,)
if use_cache:
outputs += (present_key_value,)
return outputs
@staticmethod
def llama_flash_attn_kvcache_forward(
self: LlamaAttention,
hidden_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
output_attentions: bool = False,
use_cache: bool = False,
infer_state: Optional[BatchInferState] = None,
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
assert use_cache is True, "use_cache should be set to True using this llama attention"
bsz, q_len, _ = hidden_states.size()
# NOTE might think about better way to handle transposed k and v
# key_states [bs, seq_len, num_heads, head_dim/embed_size_per_head]
# key_states_transposed [bs, num_heads, seq_len, head_dim/embed_size_per_head]
query_states = self.q_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim)
key_states = self.k_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim)
value_states = self.v_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim)
# NOTE might want to revise
# need some way to record the length of past key values cache
# since we won't return past_key_value_cache right now
if infer_state.decode_layer_id == 0: # once per model.forward
infer_state.cache_manager.past_key_values_length += q_len # seq_len
cos, sin = infer_state.position_cos, infer_state.position_sin
# print("shape ", cos.shape, query_states.view(-1, self.num_heads, self.head_dim).shape, )
rotary_embedding_fwd(query_states.view(-1, self.num_heads, self.head_dim), cos, sin)
rotary_embedding_fwd(key_states.view(-1, self.num_heads, self.head_dim), cos, sin)
def _copy_kv_to_mem_cache(layer_id, key_buffer, value_buffer, context_mem_index, mem_manager):
copy_kv_cache_to_dest(key_buffer, context_mem_index, mem_manager.key_buffer[layer_id])
copy_kv_cache_to_dest(value_buffer, context_mem_index, mem_manager.value_buffer[layer_id])
return
query_states = query_states.reshape(-1, self.num_heads, self.head_dim)
key_states = key_states.reshape(-1, self.num_heads, self.head_dim)
value_states = value_states.reshape(-1, self.num_heads, self.head_dim)
if infer_state.is_context_stage:
# first token generation
# copy key and value calculated in current step to memory manager
_copy_kv_to_mem_cache(
infer_state.decode_layer_id,
key_states,
value_states,
infer_state.context_mem_index,
infer_state.cache_manager,
)
attn_output = torch.empty_like(query_states)
llama_context_attn_fwd(
query_states,
key_states,
value_states,
attn_output,
infer_state.start_loc,
infer_state.seq_len,
infer_state.cache_manager.past_key_values_length,
)
else:
if infer_state.decode_is_contiguous:
# if decode is contiguous, then we copy to key cache and value cache in cache manager directly
cache_k = infer_state.cache_manager.key_buffer[infer_state.decode_layer_id][
infer_state.decode_mem_start : infer_state.decode_mem_end, :, :
]
cache_v = infer_state.cache_manager.value_buffer[infer_state.decode_layer_id][
infer_state.decode_mem_start : infer_state.decode_mem_end, :, :
]
cache_k.copy_(key_states)
cache_v.copy_(value_states)
else:
# if decode is not contiguous, use triton kernel to copy key and value cache
# k, v shape: [batch_size, num_heads, head_dim/embed_size_per_head
_copy_kv_to_mem_cache(
infer_state.decode_layer_id,
key_states,
value_states,
infer_state.decode_mem_index,
infer_state.cache_manager,
)
# second token and follows
# kv = torch.stack((key_states, value_states), dim=2)
# (batch_size, seqlen, nheads, headdim)
attn_output = torch.empty_like(query_states)
token_attention_fwd(
query_states,
infer_state.cache_manager.key_buffer[infer_state.decode_layer_id],
infer_state.cache_manager.value_buffer[infer_state.decode_layer_id],
attn_output,
infer_state.block_loc,
infer_state.start_loc,
infer_state.seq_len,
infer_state.cache_manager.past_key_values_length,
)
attn_output = attn_output.view(bsz, q_len, self.hidden_size)
attn_output = self.o_proj(attn_output)
# return past_key_value as None
return attn_output, None, None
def get_llama_vllm_rmsnorm_forward():
if HAS_VLLM_KERNERL:
def _vllm_rmsnorm_forward(self: LlamaRMSNorm, hidden_states: torch.Tensor):
x = hidden_states
out = torch.empty_like(x)
rms_norm(
out,
x,
self.weight.data,
self.variance_epsilon,
)
return out
return _vllm_rmsnorm_forward
else:
return None