text-generation-inference/server/text_generation/models/bloom.py
2022-11-03 16:07:54 +01:00

531 lines
22 KiB
Python

import torch
import torch.distributed
from typing import List, Optional, Tuple, Type
from accelerate import init_empty_weights
from safetensors import safe_open
from transformers import AutoTokenizer, AutoModelForCausalLM, AutoConfig
from transformers.models.bloom.parallel_layers import (
TensorParallelColumnLinear,
TensorParallelEmbedding,
TensorParallelRowLinear,
)
from transformers.modeling_outputs import CausalLMOutputWithPast
from text_generation.models import Model
from text_generation.models.types import Batch, GeneratedText
from text_generation.utils import (
initialize_torch_distributed,
weight_files,
download_weights,
)
HAS_BITS_AND_BYTES = True
try:
import bitsandbytes as bnb
from bitsandbytes.nn import Int8Params
except Exception as e:
HAS_BITS_AND_BYTES = False
torch.manual_seed(0)
class BloomBatch(Batch):
@classmethod
def concatenate(cls, batches: List["Batch"]) -> "BloomBatch":
# Used for padding
total_batch_size = sum(batch.size for batch in batches)
max_sequence_length = max(batch.max_sequence_length for batch in batches)
# Batch attributes
input_ids = {"input_ids": None, "attention_mask": None, "past_key_values": []}
requests = []
all_input_lengths = []
all_input_ids = []
next_token_choosers = []
stopping_criterias = []
# Used for slicing correctly inside the tensors
# Equivalent to a cumsum on batch sizes
start_index = 0
for i, batch in enumerate(batches):
requests.extend(batch.requests)
all_input_lengths.extend(batch.all_input_lengths)
all_input_ids.extend(batch.all_input_ids)
next_token_choosers.extend(batch.next_token_choosers)
stopping_criterias.extend(batch.stopping_criterias)
# Slicing end index for this batch
end_index = start_index + batch.size
# We only concatenate batches that did at least one step
if batch.input_ids["input_ids"].shape[1] > 1:
raise ValueError("Batch input_ids should be of shape (batch_size, 1)")
# Initialize tensors
if i == 0:
input_ids["input_ids"] = torch.empty(
(total_batch_size, 1),
dtype=batch.input_ids["input_ids"].dtype,
device=batch.input_ids["input_ids"].device,
)
input_ids["attention_mask"] = torch.zeros(
(total_batch_size, max_sequence_length),
dtype=batch.input_ids["attention_mask"].dtype,
device=batch.input_ids["attention_mask"].device,
)
# input_ids["input_ids"] is always of shape [batch_size, 1]
# We do not need to pad it
input_ids["input_ids"][start_index:end_index] = batch.input_ids["input_ids"]
# We need to slice the attention mask to remove padding from previous steps
input_ids["attention_mask"][
start_index:end_index, -batch.max_sequence_length:
] = batch.input_ids["attention_mask"][:, -batch.max_sequence_length:]
for j, past in enumerate(batch.input_ids["past_key_values"]):
past_keys = past[0]
past_values = past[1]
_, head_dim, padded_sequence_length = past_keys.shape
# Reshape the tensors to make slicing easier
past_keys = past_keys.view(
batch.size, -1, head_dim, padded_sequence_length
)
past_values = past_values.view(
batch.size, -1, padded_sequence_length, head_dim
)
num_heads = past_keys.shape[1]
# Initialize tensors
# This will run only once per layer
if j == len(input_ids["past_key_values"]):
padded_past_keys = torch.zeros(
(
total_batch_size,
num_heads,
head_dim,
max_sequence_length - 1,
),
dtype=past_keys.dtype,
device=past_keys.device,
)
padded_past_values = torch.zeros(
(
total_batch_size,
num_heads,
max_sequence_length - 1,
head_dim,
),
dtype=past_values.dtype,
device=past_values.device,
)
input_ids["past_key_values"].append(
[padded_past_keys, padded_past_values]
)
# We slice the past keys and values to remove the padding from previous batches
input_ids["past_key_values"][j][0][
start_index:end_index, :, :, -(batch.max_sequence_length - 1):
] = past_keys[:, :, :, -(batch.max_sequence_length - 1):]
input_ids["past_key_values"][j][1][
start_index:end_index, :, -(batch.max_sequence_length - 1):, :
] = past_values[:, :, -(batch.max_sequence_length - 1):, :]
# If we are on the last batch, we need to reshape the tensors
if (i + 1) == len(batches):
input_ids["past_key_values"][j][0] = input_ids["past_key_values"][
j
][0].view(total_batch_size * num_heads, head_dim, -1)
input_ids["past_key_values"][j][1] = input_ids["past_key_values"][
j
][1].view(total_batch_size * num_heads, -1, head_dim)
start_index += batch.size
return cls(
batch_id=batches[0].batch_id,
requests=requests,
all_input_lengths=all_input_lengths,
input_ids=input_ids,
all_input_ids=all_input_ids,
next_token_choosers=next_token_choosers,
stopping_criterias=stopping_criterias,
size=total_batch_size,
max_sequence_length=max_sequence_length,
)
class BLOOM(Model):
def __init__(self, model_name: str):
if not model_name.startswith("bigscience/bloom"):
raise ValueError(f"Model {model_name} is not supported")
if torch.cuda.is_available():
self.device = torch.device("cuda")
dtype = torch.bfloat16 if torch.cuda.is_bf16_supported() else torch.float16
else:
self.device = torch.device("cpu")
dtype = torch.float32
self.tokenizer = AutoTokenizer.from_pretrained(model_name, padding_side="left")
self.tokenizer.add_special_tokens({"pad_token": "[PAD]"})
self.model = AutoModelForCausalLM.from_pretrained(
model_name, torch_dtype=dtype, device_map="auto" if torch.cuda.is_available() else None
).eval()
self.num_heads = self.model.config.num_attention_heads
@property
def batch_type(self) -> Type[BloomBatch]:
return BloomBatch
def forward(
self, input_ids, attention_mask, past_key_values: Optional = None
) -> CausalLMOutputWithPast:
# Model Forward
return self.model.forward(
input_ids=input_ids,
attention_mask=attention_mask,
past_key_values=past_key_values,
use_cache=True,
)
def generate_token(
self, batch: BloomBatch
) -> Tuple[List[GeneratedText], Optional[BloomBatch]]:
# For some reason, inference_mode does not work well with GLOO which we use on CPU
context_manager = (
torch.no_grad if self.device.type == "cpu" else torch.inference_mode
)
with context_manager():
outputs = self.forward(**batch.input_ids)
# List of indices to cache
next_batch_keep_indices = []
next_batch_past_keep_indices = []
# New input_ids for next forward
next_batch_input_ids = []
next_batch_all_input_ids = []
next_all_input_lengths = []
next_batch_size = 0
next_batch_max_sequence_length = 0
# Finished requests
generated_texts: List[GeneratedText] = []
# Zipped iterator
iterator = zip(
batch.requests,
batch.all_input_lengths,
outputs.logits,
batch.next_token_choosers,
batch.stopping_criterias,
batch.all_input_ids,
)
# For each member of the batch
for i, (
request,
input_length,
logits,
next_token_chooser,
stopping_criteria,
all_tokens,
) in enumerate(iterator):
# Select next token
next_token = next_token_chooser(all_tokens, logits.unsqueeze(0)[:, -1])
# Append next token to all tokens
all_tokens = torch.cat([all_tokens, next_token])
# Evaluate stopping criteria
if stopping_criteria(all_tokens):
# Decode all tokens
output = self.tokenizer.decode(
all_tokens.squeeze(-1), skip_special_tokens=True
)
# Add to the list of finished generations with the original request
generated_texts.append(GeneratedText(request, output))
# add to the next batch
else:
next_batch_keep_indices.append(i)
# past_key_values is of shape [batch_size * num_heads, ...]
# so we need to take into account the `num_heads` stride here
next_batch_past_keep_indices.extend(
[j for j in range(i * self.num_heads, (i + 1) * self.num_heads)]
)
next_batch_input_ids.append(next_token)
next_batch_all_input_ids.append(all_tokens)
next_batch_size += 1
new_input_length = input_length + 1
next_all_input_lengths.append(new_input_length)
next_batch_max_sequence_length = max(
next_batch_max_sequence_length, new_input_length
)
# We finished all generations in the batch; there is no next batch
if not next_batch_keep_indices:
return generated_texts, None
# If we finished at least one generation
next_batch_input_ids = {"input_ids": torch.cat(next_batch_input_ids, dim=0)}
if generated_texts:
# Apply indices to attention mask, past key values and other items that need to be cached
next_batch_input_ids["attention_mask"] = batch.input_ids["attention_mask"][
next_batch_keep_indices
]
next_batch_input_ids["past_key_values"] = [
(
keys[next_batch_past_keep_indices],
values[next_batch_past_keep_indices],
)
for keys, values in outputs["past_key_values"]
]
next_batch_requests = [batch.requests[i] for i in next_batch_keep_indices]
next_batch_next_token_choosers = [
batch.next_token_choosers[i] for i in next_batch_keep_indices
]
next_batch_stopping_criterias = [
batch.stopping_criterias[i] for i in next_batch_keep_indices
]
else:
next_batch_input_ids["attention_mask"] = batch.input_ids["attention_mask"]
next_batch_input_ids["past_key_values"] = outputs["past_key_values"]
next_batch_requests = batch.requests
next_batch_next_token_choosers = batch.next_token_choosers
next_batch_stopping_criterias = batch.stopping_criterias
# Update attention_mask with padding as we added a new token to input_ids
next_batch_input_ids["attention_mask"] = torch.cat(
[
next_batch_input_ids["attention_mask"],
torch.ones((next_batch_size, 1)).to(self.device),
],
dim=1,
)
next_batch = BloomBatch(
batch_id=batch.batch_id,
requests=next_batch_requests,
all_input_lengths=next_all_input_lengths,
input_ids=next_batch_input_ids,
all_input_ids=next_batch_all_input_ids,
next_token_choosers=next_batch_next_token_choosers,
stopping_criterias=next_batch_stopping_criterias,
size=next_batch_size,
max_sequence_length=next_batch_max_sequence_length,
)
return generated_texts, next_batch
class BLOOMSharded(BLOOM):
def __init__(self, model_name: str, quantize: bool = False):
super(Model, self).__init__()
if not model_name.startswith("bigscience/bloom"):
raise ValueError(f"Model {model_name} is not supported")
self.process_group, self.rank, self.world_size = initialize_torch_distributed()
self.master = self.rank == 0
if torch.cuda.is_available():
self.device = torch.device(f"cuda:{self.rank}")
dtype = torch.float16
else:
self.device = torch.device("cpu")
dtype = torch.float32
self.tokenizer = AutoTokenizer.from_pretrained(model_name, padding_side="left")
config = AutoConfig.from_pretrained(
model_name, slow_but_exact=False, tp_parallel=True
)
config.pad_token_id = 3
self.num_heads = config.n_head // self.process_group.size()
# The flag below controls whether to allow TF32 on matmul. This flag defaults to False
# in PyTorch 1.12 and later.
torch.backends.cuda.matmul.allow_tf32 = True
# The flag below controls whether to allow TF32 on cuDNN. This flag defaults to True.
torch.backends.cudnn.allow_tf32 = True
# Only download weights for small models
if self.master and model_name == "bigscience/bloom-560m":
download_weights(model_name, extension=".safetensors")
torch.distributed.barrier(group=self.process_group)
filenames = weight_files(model_name, extension=".safetensors")
with init_empty_weights():
model = AutoModelForCausalLM.from_config(config)
torch.distributed.barrier(group=self.process_group)
self.load_weights(
model,
filenames,
quantize=quantize,
device=self.device,
rank=self.rank,
world_size=self.world_size,
)
self.model = model.eval().to(dtype)
torch.distributed.barrier(group=self.process_group)
@staticmethod
def load_weights(
model,
filenames: List[str],
quantize: bool,
device: torch.device,
rank: int,
world_size: int,
):
parameters = dict(model.named_parameters())
for file in filenames:
with safe_open(
file, framework="pt", device=str(device) if not quantize else "cpu"
) as f:
for name in f.keys():
full_name = f"transformer.{name}"
module_name, param_name = full_name.rsplit(".", 1)
module = model.get_submodule(module_name)
current_tensor = parameters[full_name]
slice_ = f.get_slice(name)
if isinstance(module, TensorParallelColumnLinear):
if param_name == "weight":
size = slice_.get_shape()[0]
block_size = size // world_size
start = rank * block_size
stop = (rank + 1) * block_size
tensor = slice_[start:stop]
tensor = tensor.transpose(1, 0)
else:
size = slice_.get_shape()[0]
block_size = size // world_size
start = rank * block_size
stop = (rank + 1) * block_size
tensor = slice_[start:stop]
elif isinstance(module, TensorParallelRowLinear):
if param_name == "weight":
size = slice_.get_shape()[1]
block_size = size // world_size
start = rank * block_size
stop = (rank + 1) * block_size
tensor = slice_[:, start:stop]
tensor = tensor.transpose(1, 0)
else:
tensor = slice_[:]
# XXX: Hack for Rowlinear to add the bias only once.
if rank != 0:
tensor = torch.zeros_like(tensor)
elif isinstance(module, TensorParallelEmbedding):
size = slice_.get_shape()[0]
block_size = size // world_size
start = rank * block_size
stop = (rank + 1) * block_size
tensor = slice_[start:stop]
else:
tensor = slice_[:]
if current_tensor.shape != tensor.shape:
raise ValueError(
f"Name {name} -- Current {current_tensor.shape} and got {tensor.shape}"
)
tensor = tensor.contiguous()
if quantize:
if not HAS_BITS_AND_BYTES:
raise ImportError(
"bitsandbytes is not available on your machine either because it is not installed "
"or you don't have a GPU.\n"
"You can install it with `pip install bitsandbytes`."
)
if (
type(module)
in [TensorParallelRowLinear, TensorParallelColumnLinear]
and param_name == "weight"
):
tensor = Int8Params(
tensor.transpose(1, 0),
has_fp16_weights=False,
requires_grad=False,
).to(device)
state = bnb.MatmulLtState()
state.threshold = 6.0
state.has_fp16_weights = False
state.memory_efficient_backward = False
state.use_pool = True
state.CB = tensor.CB
state.SCB = tensor.SCB
tensor.CB = None
tensor.SCB = None
def replace_linear(state, in_features, out_features):
def linear(input, weight, bias):
size_out = input.size()[:-1] + (out_features,)
input = input.view(-1, in_features)
out = torch.empty(
size_out, device=input.device, dtype=input.dtype
)
out = bnb.matmul(
input,
weight,
out=out.view(-1, out_features),
state=state,
threshold=state.threshold,
bias=bias,
)
if state.CB is not None:
# we converted 8-bit row major to turing/ampere format
# in the first inference pass
# we no longer need the row-major weight
del state.CB
weight.data = state.CxB
return out.view(size_out)
return linear
module.linear = replace_linear(
state, module.in_features, module.out_features
)
else:
tensor = tensor.to(device)
module._parameters[param_name] = tensor
if name == "word_embeddings.weight":
model.lm_head._parameters["weight"] = tensor
def forward(self, input_ids, attention_mask, past_key_values: Optional = None):
outputs = self.model.forward(
input_ids=input_ids,
attention_mask=attention_mask,
past_key_values=past_key_values,
use_cache=True,
)
# Logits are sharded, so we need to gather them
logits_shard = outputs.logits[:, -1, :].contiguous()
batch_size, vocab_shard_size = logits_shard.shape
vocab_size = self.world_size * vocab_shard_size
logits = [torch.empty_like(logits_shard) for _ in range(self.world_size)]
torch.distributed.all_gather(logits, logits_shard, group=self.process_group)
logits = torch.cat(logits, dim=1).view(batch_size, 1, vocab_size)
outputs.logits = logits
return outputs