pinning transformers version

This commit is contained in:
Salman Mohammadi
2025-04-08 17:17:23 +01:00
parent b98dbafc31
commit e1a8dfbe8c
7 changed files with 111 additions and 208 deletions

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@@ -1,171 +0,0 @@
"""Flex attention monkey patch"""
import sys
from typing import Optional, Tuple, Union
import torch
import transformers
def patch_flex_wrapper():
# TODO remove this patch when transformers#37285 is merged and in a release
is_torch_2_6 = torch.__version__.startswith("2.6")
is_transformers_below_4_51_1 = transformers.__version__ < "4.51.1"
if not (is_torch_2_6 and is_transformers_below_4_51_1):
return
from torch.nn.attention.flex_attention import flex_attention
class WrappedFlexAttention:
"""
We are doing a singleton class so that flex attention is compiled once when it's first called.
"""
_instance = None
_is_flex_compiled = False
_compiled_flex_attention = None
def __new__(cls, *args, **kwargs):
if cls._instance is None:
# Create a new instance if one doesn't already exist
cls._instance = super().__new__(cls)
return cls._instance
@torch.compiler.disable(recursive=False)
def __init__(self):
"""
Initialize or update the singleton instance.
"""
if not self._is_flex_compiled:
self._compiled_flex_attention = torch.compile(
flex_attention,
dynamic=False,
mode="max-autotune-no-cudagraphs",
fullgraph=True,
)
self._is_flex_compiled = True
def __call__(self):
return self._compiled_flex_attention
transformers.integrations.flex_attention.WrappedFlexAttention = WrappedFlexAttention
def patch_flex_make_mask():
is_torch_2_6 = torch.__version__.startswith("2.6")
is_transformers_eq_4_51 = transformers.__version__ == "4.51.0"
if not (is_torch_2_6 and is_transformers_eq_4_51):
return
from torch.nn.attention.flex_attention import (
BlockMask,
)
from torch.nn.attention.flex_attention import (
create_block_mask as create_block_causal_mask_flex,
)
Offset = Union[torch.Tensor, int]
def patched_make_flex_block_causal_mask(
attention_mask_2d: torch.Tensor,
attention_chunk_size: Optional[int] = None,
query_length=None,
key_length=None,
offsets: Optional[Tuple[Offset, Offset]] = None,
) -> "BlockMask":
"""
Create a block causal document mask for a batch of sequences, both packed and unpacked.
Create Block causal logic and passing it into :func:`torch.nn.attention.flex_attention.create_block_mask`.
The resultant BlockMask is a compressed representation of the full block causal
mask. BlockMask is essential for performant computation of flex attention.
See: https://pytorch.org/blog/flexattention/
Args:
attention_mask_2d (torch.Tensor): Attention mask for packed and padded sequences
of shape (batch_size, total_seq_len). e.g.
For unpacked sequence:
[[1, 1, 1, 1, 0, 0, 0],
[1, 1, 1, 1, 1, 0, 0]]
For packed sequence:
[[1, 1, 1, 2, 2, 2, 0],
[1, 1, 2, 2, 2, 3, 3]]
Returns:
BlockMask
"""
batch_size, total_seq_len = attention_mask_2d.shape
if not key_length:
key_length = total_seq_len
if not query_length:
query_length = total_seq_len
attention_mask_2d = torch.nn.functional.pad(
attention_mask_2d, value=0, pad=(0, key_length)
)
device = attention_mask_2d.device
document_ids = attention_mask_2d.clone()
if attention_chunk_size is not None:
# we create an arange, then we just // by chunk size to get [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3]
document_ids = (document_ids.fill_(1).cumsum(-1) - 1) // (
attention_chunk_size
)
# Instead of passing a tensor mask, flex attention requires a mask_mod function
# that determines which elements of QK^T should be included in the attention
# computation prior to the softmax. For sample packing, we need both the
# logic for both causal mask and document mask. See PyTorch's official
# blog post for more details: https://pytorch.org/blog/flexattention/#mask-mods
def causal_mask_mod(
batch_idx, head_idx, q_idx, kv_idx
): # pylint: disable=unused-argument
"""
Defines the logic of a block causal mask by combining both a standard causal mask
and a block diagonal document mask.
See :func:`~torchtune.modules.attention_utils.create_block_causal_mask`
for an illustration.
"""
causal_mask = q_idx >= kv_idx # not valid when decoding
document_mask = (
document_ids[batch_idx, q_idx] == document_ids[batch_idx, kv_idx]
)
padding_mask = attention_mask_2d[batch_idx, q_idx] > 0
final_mask = causal_mask & padding_mask & document_mask
return final_mask
if offsets is not None:
q_offset = offsets[0]
kv_offset = offsets[1]
def mask_mod(batch_idx, head_idx, q_idx, kv_idx):
offset_q = q_idx + q_offset
offset_kv = kv_idx + kv_offset
return causal_mask_mod(batch_idx, head_idx, offset_q, offset_kv)
else:
mask_mod = causal_mask_mod
return create_block_causal_mask_flex(
mask_mod=mask_mod,
B=batch_size,
H=None, # attention head
Q_LEN=query_length,
KV_LEN=key_length,
device=device,
_compile=True,
)
for n in tuple(sys.modules):
if ".modeling_" in n and "llama4" not in n:
if hasattr(sys.modules[n], "make_flex_block_causal_mask"):
sys.modules[n].make_flex_block_causal_mask = (
patched_make_flex_block_causal_mask
)
transformers.integrations.flex_attention.make_flex_block_causal_mask = (
patched_make_flex_block_causal_mask
)

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@@ -894,20 +894,7 @@ class ModelLoader:
"""
sample packing uses custom FA2 patch
"""
if self.cfg.flex_attention:
self.model_kwargs["attn_implementation"] = "flex_attention"
self.model_config._attn_implementation = ( # pylint: disable=protected-access
"flex_attention"
)
from axolotl.monkeypatch.attention.flex_attn import (
patch_flex_make_mask,
patch_flex_wrapper,
)
patch_flex_wrapper()
patch_flex_make_mask()
elif self.cfg.flash_attention:
if self.cfg.flash_attention:
if not self.cfg.sample_packing and self.cfg.s2_attention:
pass
self.model_kwargs["attn_implementation"] = "flash_attention_2"

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@@ -1314,8 +1314,29 @@ class AxolotlConfigWCapabilities(AxolotlInputConfig):
if version.parse(torch_version) < version.parse("2.6.0"):
raise ValueError(
"Flex attention is not supported on torch version < 2.6.0"
"Flex attention is not supported on torch version < 2.6.0."
)
elif version.parse(torch_version) < version.parse("2.7.0"):
LOG.warning(
f"You are currently using torch version {torch_version}. "
"We recommend using the latest version of torch for flex attention. "
"You may encounter unexpected issues with flex attention on older versions of torch. "
"Please upgrade to the latest stable, or nightly version of torch. "
)
transformers_version = env_capabilities.get("transformers_version")
if transformers_version is None:
import transformers
transformers_version = str(transformers.__version__).split(
"+", maxsplit=1
)[0]
if version.parse(transformers_version) < version.parse("4.45.1"):
LOG.warning(
"Transformers version < 4.45.1 is not supported with flex attention. "
)
return data
@model_validator(mode="before")