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modeling_bloom.py
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# coding=utf-8
###############################################################################
# Copyright (C) 2022-2023 Habana Labs, Ltd. an Intel Company
###############################################################################
# Changes:
# - added import os
# - overrided __package__ to allow loading from different dir
# - switched GELU impl to nn.GELU
# - added token_idx to prepare_inputs_for_generation, BloomModel, BloomBlock, BloomAttention
# - added alibi tensor code adopted from Megatron transformer.py
# - added 'update' function to update KV-cache when static shapes are enabled
# - updated cache conversion methods to use n_head from config
# - added option to preallocate and reuse kv-cache
# - transposed 'key' in kv-cache to use the same shape as 'value'
# - extracted parts of BloomAttention.forward to sub_forward to reduce number of intermediate tensors
#
# Copyright 2022 HuggingFace Inc. team and BigScience workshop.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""PyTorch BLOOM model."""
import os
import math
import warnings
from typing import Optional, Tuple, Union, Callable
__package__ = 'transformers.models.bloom'
import torch
import torch.utils.checkpoint
from torch import nn
from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, LayerNorm, MSELoss
from torch.nn import functional as F
from ...file_utils import add_code_sample_docstrings, add_start_docstrings, add_start_docstrings_to_model_forward
from ...modeling_outputs import (
BaseModelOutputWithPastAndCrossAttentions,
CausalLMOutputWithCrossAttentions,
QuestionAnsweringModelOutput,
SequenceClassifierOutputWithPast,
TokenClassifierOutput,
)
from ...modeling_utils import PreTrainedModel
from ...utils import logging
from .configuration_bloom import BloomConfig
logger = logging.get_logger(__name__)
_CHECKPOINT_FOR_DOC = "bigscience/bloom-560m"
_CONFIG_FOR_DOC = "BloomConfig"
BLOOM_PRETRAINED_MODEL_ARCHIVE_LIST = [
"bigscience/bigscience-small-testing",
"bigscience/bloom-560m",
"bigscience/bloom-1b1",
"bigscience/bloom-1b7",
"bigscience/bloom-3b",
"bigscience/bloom-7b1",
"bigscience/bloom",
]
def pre_all_reduce(layer, input):
if layer.__class__ is nn.Linear:
return input
output = torch.matmul(input, layer.weight.transpose(-1, -2))
return output
def all_reduce(layer, input):
if layer.__class__ is nn.Linear:
return input
else:
if layer.mp_group is not None:
from deepspeed import comm as dist
dist.all_reduce(input, group=layer.mp_group)
return input
def post_all_reduce(layer, input):
if layer.__class__ is nn.Linear:
return layer(input)
if layer.bias is not None:
output = input + layer.bias
return output
try:
in_place_interleave_hpu = torch.ops.hpu.in_place_interleave_
except AttributeError:
in_place_interleave_hpu = None
try:
kv_reorder_hpu = torch.ops.hpu.kv_reorder_
except AttributeError:
kv_reorder_hpu = None
def _make_causal_mask(
input_ids_shape: torch.Size, device: torch.device, past_key_values_length: int
) -> torch.BoolTensor:
"""
Make causal mask used for self-attention.
"""
batch_size, target_length = input_ids_shape
mask = torch.empty((target_length, target_length + past_key_values_length), dtype=torch.bool, device=device)
# ONNX doesn't support `torch.Tensor.triu` properly, thus we use this workaround
seq_ids = torch.arange(target_length, device=device)
mask[:, past_key_values_length:] = seq_ids[:, None] < seq_ids[None, :]
if past_key_values_length > 0:
mask[:, :past_key_values_length] = False
expanded_mask = mask[None, None, :, :].expand(batch_size, 1, target_length, target_length + past_key_values_length)
return expanded_mask
def _expand_mask(mask: torch.Tensor, tgt_length: int) -> torch.BoolTensor:
"""
Expands attention_mask from `[batch_size, src_length]` to `[batch_size, 1, tgt_length, src_length]`.
"""
batch_size, src_length = mask.shape
tgt_length = tgt_length if tgt_length is not None else src_length
expanded_mask = ~(mask[:, None, None, :].to(torch.bool))
return expanded_mask.expand(batch_size, 1, tgt_length, src_length)
def build_alibi_tensor(attention_mask: torch.Tensor, num_heads: int, dtype: torch.dtype) -> torch.Tensor:
"""
Link to paper: https://arxiv.org/abs/2108.12409 Alibi tensor is not causal as the original paper mentions, it
relies on a translation invariance of softmax for quick implementation: with l being a tensor, and a fixed value
`softmax(l+a) = softmax(l)`. Based on
https://github.com/ofirpress/attention_with_linear_biases/blob/a35aaca144e0eb6b789dfcb46784c4b8e31b7983/fairseq/models/transformer.py#L742
TODO @thomasw21 this doesn't work as nicely due to the masking strategy, and so masking varies slightly.
Args:
Returns tensor shaped (batch_size * num_heads, 1, max_seq_len)
attention_mask (`torch.Tensor`):
Token-wise attention mask, this should be of shape (batch_size, max_seq_len).
num_heads (`int`, *required*):
number of heads
dtype (`torch.dtype`, *optional*, default=`torch.bfloat16`):
dtype of the output tensor
"""
batch_size, seq_length = attention_mask.shape
closest_power_of_2 = 2 ** math.floor(math.log2(num_heads))
base = torch.tensor(
2 ** (-(2 ** -(math.log2(closest_power_of_2) - 3))), device=attention_mask.device, dtype=torch.float32
)
powers = torch.arange(1, 1 + closest_power_of_2, device=attention_mask.device, dtype=torch.int32)
slopes = torch.pow(base, powers)
if closest_power_of_2 != num_heads:
extra_base = torch.tensor(
2 ** (-(2 ** -(math.log2(2 * closest_power_of_2) - 3))), device=attention_mask.device, dtype=torch.float32
)
num_remaining_heads = min(closest_power_of_2, num_heads - closest_power_of_2)
extra_powers = torch.arange(1, 1 + 2 * num_remaining_heads, 2, device=attention_mask.device, dtype=torch.int32)
slopes = torch.cat([slopes, torch.pow(extra_base, extra_powers)], dim=0)
# Note: alibi will added to the attention bias that will be applied to the query, key product of attention
# => therefore alibi will have to be of shape (batch_size, num_heads, query_length, key_length)
# => here we set (batch_size=1, num_heads=num_heads, query_length=1, key_length=max_length)
# => the query_length dimension will then be broadcasted correctly
# This is more or less identical to T5's relative position bias:
# https://github.com/huggingface/transformers/blob/f681437203baa7671de3174b0fa583c349d9d5e1/src/transformers/models/t5/modeling_t5.py#L527
# code taken from Megatron transformer.py
batch_size = attention_mask.size()[0]
max_seq_len = attention_mask.size()[1]
alibi = slopes.unsqueeze(1).unsqueeze(1) * torch.arange(max_seq_len, device=attention_mask.device).unsqueeze(0).unsqueeze(0).expand(
num_heads, -1, -1)
#Select the part of the tensor that corresponds to our tensor parallel index.
tp_world_size = int(os.environ.get('WORLD_SIZE', 1))
tp_index = int(os.environ.get('RANK', 0))
alibi = alibi.reshape((tp_world_size, -1, *alibi.shape[1:]))[tp_index]
alibi = alibi.repeat(batch_size, 1, 1)
return alibi.to(dtype)
def dropout_add(x: torch.Tensor, residual: torch.Tensor, prob: float, training: bool) -> torch.Tensor:
"""
Dropout add function
Args:
x (`torch.tensor`, *required*):
input tensor
residual (`torch.tensor`, *required*):
esidual tensor
prob (`float`, *required*):
dropout probability
training (`bool`, *required*):
training mode
"""
out = F.dropout(x, p=prob, training=training)
out = residual + out
return out
def bloom_gelu_forward(x: torch.Tensor) -> torch.Tensor:
"""
Custom bias GELU function. Adapted from Megatron-DeepSpeed code. Here we use a simple implementation (inference) to
make the model jitable.
Args:
x (`torch.tensor`, *required*):
input hidden states
"""
return x * 0.5 * (1.0 + torch.tanh(0.79788456 * x * (1 + 0.044715 * x * x)))
def bloom_gelu_back(g: torch.Tensor, x: torch.Tensor) -> torch.Tensor:
"""
gradient of tanh approximation of gelu gradient of actual gelu is: 0.5 * (1. + torch.erf(x * 0.70710678)) +
0.3989423 * x * torch.exp(-0.5 * x * x)
Args:
g (`torch.tensor`, *required*):
gradient output tensor
x (`torch.tensor`, *required*):
input tensor
"""
x = x[0] # x is a tuple of 1 element, needs to unpack it first
tanh_out = torch.tanh(0.79788456 * x * (1 + 0.044715 * x * x))
# sqrt(2/pi) * 3 * 0.044715 -> 0.1070322243
ff = 0.5 * x * ((1 - tanh_out * tanh_out) * (0.79788456 + 0.1070322243 * x * x)) + 0.5 * (1 + tanh_out)
return ff * g
class GeLUFunction(torch.autograd.Function):
@staticmethod
def forward(ctx, input: torch.Tensor) -> torch.Tensor:
ctx.save_for_backward(input)
return bloom_gelu_forward(input)
@staticmethod
def backward(ctx, grad_output: torch.Tensor) -> torch.Tensor:
input = ctx.saved_tensors
tmp = bloom_gelu_back(grad_output, input)
return tmp
class BloomGelu(nn.Module):
"""
BloomBiasGelu wrapper function that make use of the simple function on inference mode to make the model
torchscriptable and use the autograd function in training mode to get the accurate results of the gradients Partly
copied from Megatron-DeepSpeed code and adapted for our needs
See here why autograd functions are not torchscriptable: https://github.com/pytorch/pytorch/issues/22329
"""
def __init__(self):
super().__init__()
def forward(self, x: torch.Tensor) -> torch.Tensor:
if self.training:
return GeLUFunction.apply(x)
else:
return bloom_gelu_forward(x)
class CacheReorder(object):
def __init__(self):
super().__init__()
self.input_length = 0
self.num_beams = 0
self.device = torch.device('cpu')
def prepare_for_new_input(self, input_length, num_beams, batch_size, device):
self.num_beams = num_beams
self.device = device
if device.type == "hpu" and self.input_length != input_length:
self.start = torch.full([batch_size], input_length, dtype=torch.int32, device=device)
self.end = torch.full([batch_size], input_length, dtype=torch.int32, device=device)
self.mul = torch.tensor([[64, 16, 4, 1]], dtype=torch.int32, device=device)
self.input_length = input_length
def prepare_next_beam_idx(self, beam_idx):
if self.device.type != "hpu" or kv_reorder_hpu is None or self.num_beams != 4:
return beam_idx
else:
self.end.add_(1)
indices = beam_idx.view(-1, self.num_beams)
indices = torch.sum(indices * self.mul, axis=-1).to(torch.uint8)
return indices
def reorder_beams_first_token(self, tensor, beam_idx):
if self.device.type != "hpu" or in_place_interleave_hpu is None or self.num_beams != 4:
updated = tensor.index_select(0, beam_idx)
tensor.copy_(updated)
else:
in_place_interleave_hpu(tensor)
def reorder_beams_next_token(self, tensor, beam_idx):
if self.device.type != "hpu" or kv_reorder_hpu is None or self.num_beams != 4:
updated = tensor.index_select(0, beam_idx)
tensor.copy_(updated)
else:
kv_reorder_hpu(tensor, self.start, self.end, beam_idx)
class CacheUpdate(nn.Module):
def __init__(self):
super().__init__()
def forward(self, prev, cur, dim, idx):
orig_cur = cur
cur = cur.to(dtype=prev.dtype)
if prev.shape[0] != cur.shape[0]:
assert prev.shape[0] % cur.shape[0] == 0, f'Cannot update kv-cache. BatchSize changed! {prev.shape[0]} vs {cur.shape[0]}'
# Repeat to accomodate bs/beam changes
cur = cur.repeat(prev.shape[0] // cur.shape[0], 1, 1)
if prev.shape[1] != cur.shape[1] and cur.shape[1] != 1:
# Pad to accomodate input bucketing
padding_len = prev.shape[1] - cur.shape[1]
cur = torch.nn.functional.pad(cur, (0, 0, 0, padding_len))
if prev.shape == cur.shape:
# Initialize
prev.copy_(cur)
return orig_cur
if os.environ.get('SKIP_KV_CACHE_UPDATE', '0') != '0':
# Skip update
return prev
assert cur.shape[1] == 1, f'Cannot update kv-cache. Unsupported shapes. prev:{prev.shape} cur:{cur.shape}'
if idx is not None:
prev.index_copy_(dim, idx - 1, cur)
prev_cast = prev.to(orig_cur.dtype)
return prev_cast
else:
return torch.cat((prev, cur), dim=dim)
class BloomAttention(nn.Module):
def __init__(self, config: BloomConfig):
super().__init__()
self.pretraining_tp = config.pretraining_tp
self.slow_but_exact = config.slow_but_exact
self.hidden_size = config.hidden_size
self.num_heads = config.n_head
self.head_dim = self.hidden_size // self.num_heads
self.split_size = self.hidden_size
self.hidden_dropout = config.hidden_dropout
self.past_key = None
self.past_value = None
self.kv_cache_fp8 = False
self.v_update = CacheUpdate()
self.k_update = CacheUpdate()
self.cache_reorder = CacheReorder()
if self.head_dim * self.num_heads != self.hidden_size:
raise ValueError(
f"`hidden_size` must be divisible by num_heads (got `hidden_size`: {self.hidden_size} and `num_heads`:"
f" {self.num_heads})."
)
# Layer-wise attention scaling
self.inv_norm_factor = 1.0 / math.sqrt(self.head_dim)
self.beta = 1.0
self.query_key_value = nn.Linear(self.hidden_size, 3 * self.hidden_size, bias=True)
self.dense = nn.Linear(self.hidden_size, self.hidden_size)
self.attention_dropout = nn.Dropout(config.attention_dropout)
def _split_heads(self, fused_qkv: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
"""
Split the last dimension into (num_heads, head_dim) without making any copies, results share same memory
storage as `fused_qkv`
Args:
fused_qkv (`torch.tensor`, *required*): [batch_size, seq_length, num_heads * 3 * head_dim]
Returns:
query: [batch_size, seq_length, num_heads, head_dim] key: [batch_size, seq_length, num_heads, head_dim]
value: [batch_size, seq_length, num_heads, head_dim]
"""
batch_size, seq_length, three_times_hidden_size = fused_qkv.shape
fused_qkv = fused_qkv.view(batch_size, seq_length, self.num_heads, 3, self.head_dim)
return fused_qkv[..., 0, :], fused_qkv[..., 1, :], fused_qkv[..., 2, :]
def _merge_heads(self, x: torch.Tensor) -> torch.Tensor:
"""
Merge heads together over the last dimenstion
Args:
x: (`torch.tensor`, *required*): [batch_size * num_heads, seq_length, head_dim]
Returns:
torch.tensor: [batch_size, seq_length, num_heads * head_dim]
"""
# What we want to achieve is:
# batch_size * num_heads, seq_length, head_dim -> batch_size, seq_length, num_heads * head_dim
batch_size_and_num_heads, seq_length, _ = x.shape
batch_size = batch_size_and_num_heads // self.num_heads
# First view to decompose the batch size
# batch_size * num_heads, seq_length, head_dim -> batch_size, num_heads, seq_length, head_dim
x = x.view(batch_size, self.num_heads, seq_length, self.head_dim)
# batch_size, num_heads, seq_length, head_dim -> batch_size, seq_length, num_heads, head_dim
x = x.permute(0, 2, 1, 3)
# batch_size, seq_length, num_heads, head_dim -> batch_size, seq_length, num_heads * head_dim
return x.reshape(batch_size, seq_length, self.num_heads * self.head_dim)
def allocate_kv_cache(self, batch_size, seq_len, kv_cache_fp8):
key_shape = (batch_size * self.num_heads, seq_len, self.head_dim)
value_shape = (batch_size * self.num_heads, seq_len, self.head_dim)
if self.past_key is None or self.past_key.shape != key_shape:
device = self.query_key_value.weight.device
dtype = self.query_key_value.weight.dtype
if kv_cache_fp8:
self.kv_cache_fp8 = True
dtype = torch.float8_e4m3fn
self.past_key = torch.empty(key_shape, dtype=dtype, device=device)
self.past_value = torch.empty(value_shape, dtype=dtype, device=device)
def prepare_next_beam_idx(self, beam_idx: torch.LongTensor):
return self.cache_reorder.prepare_next_beam_idx(beam_idx)
def prepare_for_new_input(self, input_length: int, num_beams: int, batch_size: int, device: torch.device):
self.cache_reorder.prepare_for_new_input(input_length, num_beams, batch_size, device)
def reorder(self, tensor: torch.LongTensor, beam_idx: torch.LongTensor, reorder_fn : Callable):
cache_4D = tensor.view(-1, self.num_heads, tensor.size(-2), tensor.size(-1))
return reorder_fn(cache_4D, beam_idx)
def reorder_kv_cache(self, beam_idx: torch.LongTensor, reorder_fn : Callable):
if self.past_key is None:
return (None, None)
else:
self.reorder(self.past_key, beam_idx, reorder_fn)
self.reorder(self.past_value, beam_idx, reorder_fn)
return (self.past_key.shape, self.past_value.shape)
def reorder_kv_cache_first_token(self, beam_idx: torch.LongTensor):
return self.reorder_kv_cache(beam_idx, self.cache_reorder.reorder_beams_first_token)
def reorder_kv_cache_next_token(self, beam_idx: torch.LongTensor):
return self.reorder_kv_cache(beam_idx, self.cache_reorder.reorder_beams_next_token)
def pre_attn_forward(
self,
hidden_states: torch.Tensor,
alibi: torch.Tensor,
attention_mask: torch.Tensor,
layer_past: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
head_mask: Optional[torch.Tensor] = None,
use_cache: bool = False,
output_attentions: bool = False,
token_idx: Optional[torch.Tensor] = None,
reuse_cache: Optional[bool] = False
):
fused_qkv = self.query_key_value(hidden_states) # [batch_size, seq_length, 3 x hidden_size]
# 3 x [batch_size, seq_length, num_heads, head_dim]
(query_layer, key_layer, value_layer) = self._split_heads(fused_qkv)
batch_size, q_length, _, _ = query_layer.shape
query_layer = query_layer.transpose(1, 2).reshape(batch_size * self.num_heads, q_length, self.head_dim)
key_layer = key_layer.transpose(1, 2).reshape(batch_size * self.num_heads, q_length, self.head_dim)
value_layer = value_layer.transpose(1, 2).reshape(batch_size * self.num_heads, q_length, self.head_dim)
if layer_past is not None or reuse_cache:
if reuse_cache:
past_key, past_value = self.past_key, self.past_value
else:
past_key, past_value = layer_past
# concatenate along seq_length dimension:
# - key: [batch_size * self.num_heads, head_dim, kv_length]
# - value: [batch_size * self.num_heads, kv_length, head_dim]
key_layer = self.k_update(past_key, key_layer, 1, token_idx)
value_layer = self.v_update(past_value, value_layer, 1, token_idx)
_, kv_length, _ = key_layer.shape
if use_cache is True:
if reuse_cache:
present = (key_layer.shape, value_layer.shape)
else:
present = (key_layer, value_layer)
else:
present = None
# [batch_size * num_heads, q_length, kv_length]
# we use `torch.Tensor.baddbmm` instead of `torch.baddbmm` as the latter isn't supported by TorchScript v1.11
matmul_result = alibi.baddbmm(
batch1=query_layer,
batch2=key_layer.transpose(1, 2),
beta=self.beta,
alpha=self.inv_norm_factor,
)
# change view to [batch_size, num_heads, q_length, kv_length]
attention_scores = matmul_result.view(batch_size, self.num_heads, q_length, kv_length)
# cast attention scores to fp32, compute scaled softmax and cast back to initial dtype - [batch_size, num_heads, q_length, kv_length]
input_dtype = attention_scores.dtype
# `float16` has a minimum value of -65504.0, whereas `bfloat16` and `float32` have a minimum value of `-3.4e+38`
if input_dtype == torch.float16:
attention_scores = attention_scores.to(torch.float)
attn_weights = torch.masked_fill(attention_scores, attention_mask, torch.finfo(attention_scores.dtype).min)
attention_probs = F.softmax(attn_weights, dim=-1, dtype=torch.float32).to(input_dtype)
# [batch_size, num_heads, q_length, kv_length]
attention_probs = self.attention_dropout(attention_probs)
if head_mask is not None:
attention_probs = attention_probs * head_mask
# change view [batch_size x num_heads, q_length, kv_length]
attention_probs_reshaped = attention_probs.view(batch_size * self.num_heads, q_length, kv_length)
# matmul: [batch_size * num_heads, q_length, head_dim]
context_layer = torch.bmm(attention_probs_reshaped, value_layer)
# change view [batch_size, num_heads, q_length, head_dim]
context_layer = self._merge_heads(context_layer)
# hidden_states = context_layer
hidden_states = pre_all_reduce(self.dense, context_layer)
if output_attentions:
return hidden_states, present, attention_probs
return hidden_states, present, None
def attention_all_reduce(self, hidden_states: torch.Tensor) -> torch.Tensor:
all_reduce(self.dense, hidden_states)
def post_attn_forward(self,
input: torch.Tensor,
residual: torch.Tensor):
intermediate_output = post_all_reduce(self.dense, input)
output_tensor = dropout_add(intermediate_output, residual, self.hidden_dropout, self.training)
return output_tensor
def forward(
self,
hidden_states: torch.Tensor,
residual: torch.Tensor,
alibi: torch.Tensor,
attention_mask: torch.Tensor,
layer_past: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
head_mask: Optional[torch.Tensor] = None,
use_cache: bool = False,
output_attentions: bool = False,
token_idx: Optional[torch.Tensor] = None,
reuse_cache: Optional[bool] = False,
):
context_layer, present, attention_probs = self.pre_attn_forward(hidden_states, alibi, attention_mask, layer_past, head_mask, use_cache, output_attentions, token_idx, reuse_cache)
# aggregate results across tp ranks. See here: https://github.com/pytorch/pytorch/issues/76232
if self.pretraining_tp > 1 and self.slow_but_exact:
slices = self.hidden_size / self.pretraining_tp
output_tensor = torch.zeros_like(context_layer)
for i in range(self.pretraining_tp):
output_tensor = output_tensor + F.linear(
context_layer[:, :, int(i * slices) : int((i + 1) * slices)],
self.dense.weight[:, int(i * slices) : int((i + 1) * slices)],
)
else:
output_tensor = self.dense(context_layer)
output_tensor = dropout_add(output_tensor, residual, self.hidden_dropout, self.training)
outputs = (output_tensor, present)
if output_attentions:
outputs += (attention_probs,)
return outputs
class BloomMLP(nn.Module):
def __init__(self, config: BloomConfig):
super().__init__()
hidden_size = config.hidden_size
self.pretraining_tp = config.pretraining_tp
self.slow_but_exact = config.slow_but_exact
self.dense_h_to_4h = nn.Linear(hidden_size, 4 * hidden_size)
self.gelu_impl = nn.GELU(approximate='tanh')
self.dense_4h_to_h = nn.Linear(4 * hidden_size, hidden_size)
self.hidden_dropout = config.hidden_dropout
def forward(self, hidden_states: torch.Tensor, residual: torch.Tensor) -> torch.Tensor:
hidden_states = self.gelu_impl(self.dense_h_to_4h(hidden_states))
if self.pretraining_tp > 1 and self.slow_but_exact:
intermediate_output = torch.zeros_like(residual)
slices = self.dense_4h_to_h.weight.shape[-1] / self.pretraining_tp
for i in range(self.pretraining_tp):
intermediate_output = intermediate_output + F.linear(
hidden_states[:, :, int(i * slices) : int((i + 1) * slices)],
self.dense_4h_to_h.weight[:, int(i * slices) : int((i + 1) * slices)],
)
else:
intermediate_output = self.dense_4h_to_h(hidden_states)
output = dropout_add(intermediate_output, residual, self.hidden_dropout, self.training)
return output
def pre_mlp_forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
hidden_states = self.gelu_impl(self.dense_h_to_4h(hidden_states))
output = pre_all_reduce(self.dense_4h_to_h, hidden_states)
return output
def mlp_all_reduce(self, hidden_states: torch.Tensor) -> torch.Tensor:
all_reduce(self.dense_4h_to_h, hidden_states)
def post_mlp_forward(self, input: torch.Tensor, residual: torch.Tensor) -> torch.Tensor:
intermediate_output = post_all_reduce(self.dense_4h_to_h, input)
output = dropout_add(intermediate_output, residual, self.hidden_dropout, self.training)
return output
class BloomBlock(nn.Module):
def __init__(self, config: BloomConfig):
super().__init__()
hidden_size = config.hidden_size
self.input_layernorm = LayerNorm(hidden_size, eps=config.layer_norm_epsilon)
self.num_heads = config.n_head
self.self_attention = BloomAttention(config)
self.post_attention_layernorm = LayerNorm(hidden_size, eps=config.layer_norm_epsilon)
self.mlp = BloomMLP(config)
self.apply_residual_connection_post_layernorm = config.apply_residual_connection_post_layernorm
self.hidden_dropout = config.hidden_dropout
def allocate_kv_cache(self, batch_size, seq_len, kv_cache_fp8):
self.self_attention.allocate_kv_cache(batch_size, seq_len, kv_cache_fp8)
def prepare_for_new_input(self, input_length: int, num_beams: int, batch_size: int, device: torch.device):
self.self_attention.prepare_for_new_input(input_length, num_beams, batch_size, device)
def prepare_next_beam_idx(self, beam_idx: torch.LongTensor):
return self.self_attention.prepare_next_beam_idx(beam_idx)
def reorder_kv_cache_first_token(self, beam_idx: torch.LongTensor):
return self.self_attention.reorder_kv_cache_first_token(beam_idx)
def reorder_kv_cache_next_token(self, beam_idx: torch.LongTensor):
return self.self_attention.reorder_kv_cache_next_token(beam_idx)
def pre_attn(
self,
hidden_states: torch.Tensor,
alibi: torch.Tensor,
attention_mask: torch.Tensor,
layer_past: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
head_mask: Optional[torch.Tensor] = None,
use_cache: bool = False,
output_attentions: bool = False,
token_idx: Optional[torch.Tensor] = None,
reuse_cache: Optional[bool] = None,
):
# hidden_states: [batch_size, seq_length, hidden_size]
# Layer norm at the beginning of the transformer layer.
layernorm_output = self.input_layernorm(hidden_states)
# Layer norm post the self attention.
if self.apply_residual_connection_post_layernorm:
residual = layernorm_output
else:
residual = hidden_states
hidden_states, present, attention_probs = self.self_attention.pre_attn_forward(layernorm_output, alibi, attention_mask, layer_past, head_mask, use_cache, output_attentions, token_idx, reuse_cache)
return hidden_states, present, attention_probs, residual
def post_attn_pre_mlp(self, input, residual):
attention_output = self.self_attention.post_attn_forward(input, residual)
layernorm_output = self.post_attention_layernorm(attention_output)
# Get residual
if self.apply_residual_connection_post_layernorm:
residual = layernorm_output
else:
residual = attention_output
output = self.mlp.pre_mlp_forward(layernorm_output)
return output, residual
def post_mlp(self, input, resiudal):
output = self.mlp.post_mlp_forward(input, resiudal)
return output
def forward(
self,
hidden_states: torch.Tensor,
alibi: torch.Tensor,
attention_mask: torch.Tensor,
layer_past: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
head_mask: Optional[torch.Tensor] = None,
use_cache: bool = False,
output_attentions: bool = False,
token_idx: Optional[torch.Tensor] = None,
reuse_cache: Optional[bool] = None,
):
output_pre_attn, present, attention_probs, resiudal_attn = self.pre_attn(hidden_states, alibi, attention_mask, layer_past, head_mask, use_cache, output_attentions, token_idx, reuse_cache)
self.self_attention.attention_all_reduce(output_pre_attn)
output_post_attn_pre_mlp, resiudal_mlp = self.post_attn_pre_mlp(output_pre_attn, resiudal_attn)
self.mlp.mlp_all_reduce(output_post_attn_pre_mlp)
output_mlp = self.post_mlp(output_post_attn_pre_mlp, resiudal_mlp)
outputs = (present,)
if output_attentions:
outputs += (attention_probs,)
if use_cache:
outputs = (output_mlp,) + outputs
else:
outputs = (output_mlp,) + outputs[1:]
return outputs
class BloomPreTrainedModel(PreTrainedModel):
_keys_to_ignore_on_load_missing = [r"h.*.self_attention.scale_mask_softmax.causal_mask", r"lm_head.weight"]
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = BloomConfig
base_model_prefix = "transformer"
supports_gradient_checkpointing = True
_no_split_modules = ["BloomBlock"]
def __init__(self, *inputs, **kwargs):
super().__init__(*inputs, **kwargs)
def _init_weights(self, module: nn.Module):
"""Initialize the weights."""
if isinstance(module, nn.Linear):
# Slightly different from the TF version which uses truncated_normal for initialization
# cf https://github.com/pytorch/pytorch/pull/5617
module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
if module.bias is not None:
module.bias.data.zero_()
elif isinstance(module, nn.Embedding):
module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
if module.padding_idx is not None:
module.weight.data[module.padding_idx].zero_()
elif isinstance(module, LayerNorm):
module.bias.data.zero_()
module.weight.data.fill_(1.0)
def _set_gradient_checkpointing(self, module: nn.Module, value: bool = False):
if isinstance(module, BloomModel):
module.gradient_checkpointing = value
def _convert_to_standard_cache(
self, past_key_value: Tuple[Tuple[torch.Tensor, torch.Tensor]]
) -> Tuple[Tuple[torch.Tensor, torch.Tensor]]:
"""
Standardizes the format of the cache so as to match most implementations, i.e. to tuple(tuple([batch_size,
num_heads, ...]))
"""
batch_size_times_num_heads, seq_length, head_dim = past_key_value[0][0].shape
tp_world_size = int(os.environ.get('WORLD_SIZE', 1))
num_heads = self.config.n_head // tp_world_size
batch_size = batch_size_times_num_heads // num_heads
# key: [batch_size * num_heads, seq_length, head_dim] -> [batch_size, num_heads, seq_length, head_dim]
# value: [batch_size * num_heads, seq_length, head_dim] -> [batch_size, num_heads, seq_length, head_dim]
return tuple(
(
layer_past[0].view(batch_size, num_heads, seq_length, head_dim),
layer_past[1].view(batch_size, num_heads, seq_length, head_dim),
)
for layer_past in past_key_value
)
def _convert_to_bloom_cache(
self, past_key_value: Tuple[Tuple[torch.Tensor, torch.Tensor]]
) -> Tuple[Tuple[torch.Tensor, torch.Tensor]]:
"""
Converts the cache to the format expected by Bloom, i.e. to tuple(tuple([batch_size * num_heads, ...]))
"""
batch_size, num_heads, seq_length, head_dim = past_key_value[0][0].shape
batch_size_times_num_heads = batch_size * num_heads
# key: [batch_size, num_heads, seq_length, head_dim] -> [batch_size * num_heads, seq_length, head_dim]
# value: [batch_size, num_heads, seq_length, head_dim] -> [batch_size * num_heads, seq_length, head_dim]
return tuple(
(
layer_past[0].view(batch_size_times_num_heads, seq_length, head_dim),
layer_past[1].view(batch_size_times_num_heads, seq_length, head_dim),
)
for layer_past in past_key_value
)
BLOOM_START_DOCSTRING = r"""
This model inherits from [`PreTrainedModel`]. Check the superclass documentation for the generic methods the
library implements for all its model (such as downloading or saving, resizing the input embeddings etc.)
This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass.
Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage
and behavior.
Parameters:
config ([`BloomConfig`]): Model configuration class with all the parameters of the model.
Initializing with a config file does not load the weights associated with the model, only the
configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights.
"""
BLOOM_INPUTS_DOCSTRING = r"""
Args:
input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`):
`input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values[0][0].shape[2]`
(`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary.
If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as
`input_ids`.
Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
[`PreTrainedTokenizer.__call__`] for details.
[What are input IDs?](../glossary#input-ids)
past_key_values (`Tuple[Tuple[torch.Tensor]]` of length `config.n_layers`):
Contains precomputed hidden-states (key and values in the attention blocks) as computed by the model (see
`past_key_values` output below). Can be used to speed up sequential decoding. The `input_ids` which have
their past given to this model should not be passed as `input_ids` as they have already been computed.
Each element of `past_key_values` is a tuple (past_key, past_value):
- past_key: [batch_size * num_heads, head_dim, kv_length]
- past_value: [batch_size * num_heads, kv_length, head_dim]
attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*):
Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
- 1 for tokens that are **not masked**,
- 0 for tokens that are **masked**.
[What are attention masks?](../glossary#attention-mask)
head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*):
Mask to nullify selected heads of the self-attention modules. Mask values selected in `[0, 1]`:
- 1 indicates the head is **not masked**,
- 0 indicates the head is **masked**.
inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This
is useful if you want more control over how to convert `input_ids` indices into associated vectors than the
model's internal embedding lookup matrix.
If `past_key_values` is used, optionally only the last `inputs_embeds` have to be input (see
`past_key_values`).
use_cache (`bool`, *optional*):
If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see
`past_key_values`).
output_attentions (`bool`, *optional*):
Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned
tensors for more detail.
output_hidden_states (`bool`, *optional*):
Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
more detail.
return_dict (`bool`, *optional*):
Whether or not to return a [`~file_utils.ModelOutput`] instead of a plain tuple.
"""
@add_start_docstrings(
"The bare Bloom Model transformer outputting raw hidden-states without any specific head on top.",
BLOOM_START_DOCSTRING,
)
class BloomModel(BloomPreTrainedModel):
def __init__(self, config: BloomConfig):
super().__init__(config)
self.embed_dim = config.hidden_size
self.num_heads = config.n_head
# Embedding + LN Embedding
self.word_embeddings = nn.Embedding(config.vocab_size, self.embed_dim)
self.word_embeddings_layernorm = LayerNorm(self.embed_dim, eps=config.layer_norm_epsilon)
# Transformer blocks
self.h = nn.ModuleList([BloomBlock(config) for _ in range(config.num_hidden_layers)])
# Final Layer Norm
self.ln_f = LayerNorm(self.embed_dim, eps=config.layer_norm_epsilon)
self.gradient_checkpointing = False
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.word_embeddings
def _prepare_attn_mask(
self, attention_mask: torch.Tensor, input_shape: Tuple[int, int], past_key_values_length: int
) -> torch.BoolTensor:
# create causal mask
# [batch_size, seq_length] -> [batch_size, 1, tgt_length, src_length]
combined_attention_mask = None
device = attention_mask.device
_, src_length = input_shape
if src_length > 1:
combined_attention_mask = _make_causal_mask(
input_shape, device=device, past_key_values_length=past_key_values_length
)
# [batch_size, seq_length] -> [batch_size, 1, tgt_length, src_length]
expanded_attn_mask = _expand_mask(attention_mask, tgt_length=src_length)
combined_attention_mask = (
expanded_attn_mask if combined_attention_mask is None else expanded_attn_mask | combined_attention_mask
)
return combined_attention_mask
def set_input_embeddings(self, new_embeddings: torch.Tensor):
self.word_embeddings = new_embeddings
def allocate_kv_cache(self, batch_size, max_seq_len, kv_cache_fp8):
for layer in self.h:
layer.allocate_kv_cache(batch_size, max_seq_len, kv_cache_fp8)
def prepare_for_new_input(self, input_length: int, num_beams: int, batch_size: int, device: torch.device):
for layer in self.h:
layer.prepare_for_new_input(input_length, num_beams, batch_size, device)
def reorder_kv_cache_first_token(self, beam_idx: torch.LongTensor):
return tuple(layer.reorder_kv_cache_first_token(beam_idx) for layer in self.h)
def reorder_kv_cache_next_token(self, beam_idx: torch.LongTensor):
beam_idx = self.h[0].prepare_next_beam_idx(beam_idx) if self.h else None
return tuple(layer.reorder_kv_cache_next_token(beam_idx) for layer in self.h)
@add_start_docstrings_to_model_forward(BLOOM_INPUTS_DOCSTRING)
@add_code_sample_docstrings(
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=BaseModelOutputWithPastAndCrossAttentions,
config_class=_CONFIG_FOR_DOC,
)
def forward(
self,
input_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[Tuple[Tuple[torch.Tensor, torch.Tensor], ...]] = None,
attention_mask: Optional[torch.Tensor] = None,
head_mask: Optional[torch.LongTensor] = None,
inputs_embeds: Optional[torch.LongTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
token_idx: Optional[torch.Tensor] = None,
reuse_cache: Optional[bool] = None,
**deprecated_arguments,
) -> Union[Tuple[torch.Tensor, ...], BaseModelOutputWithPastAndCrossAttentions]:
if deprecated_arguments.pop("position_ids", False) is not False:
# `position_ids` could have been `torch.Tensor` or `None` so defaulting pop to `False` allows to detect if users were passing explicitly `None`
warnings.warn(
"`position_ids` have no functionality in BLOOM and will be removed in v5.0.0. You can safely ignore"
" passing `position_ids`.",
FutureWarning,
)
if len(deprecated_arguments) > 0:
raise ValueError(f"Got unexpected arguments: {deprecated_arguments}")
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
use_cache = use_cache if use_cache is not None else self.config.use_cache
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
if input_ids is not None and inputs_embeds is not None:
raise ValueError("You cannot specify both input_ids and 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 input_ids or inputs_embeds")
if past_key_values is None:
past_key_values = tuple([None] * len(self.h))
# Prepare head mask if needed
# 1.0 in head_mask indicate we keep the head
# attention_probs has shape batch_size x num_heads x N x N
# head_mask has shape n_layer x batch x num_heads x N x N
head_mask = self.get_head_mask(head_mask, self.config.n_layer)
if inputs_embeds is None:
inputs_embeds = self.word_embeddings(input_ids)
hidden_states = self.word_embeddings_layernorm(inputs_embeds)
presents = () if use_cache else None