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ColossalAI/extensions/flash_attention/flash_attention_npu.py

74 lines
2.3 KiB

from ..base_extension import _Extension
class FlashAttentionNpuExtension(_Extension):
def __init__(self):
super().__init__(name="flash_attention_npu", support_aot=False, support_jit=False)
def is_hardware_available(self) -> bool:
try:
import torch_npu # noqa
return True
except:
return False
def assert_hardware_compatible(self) -> bool:
pass
def build_aot(self) -> None:
raise NotImplementedError(
"Flash Attention NPU does not require ahead-of-time compilation. Please use it by installing torch_npu."
)
def build_jit(self) -> None:
raise NotImplementedError(
"Flash Attention NPU does not require just-in-time compilation. Please use it by installing torch_npu."
)
def load(self):
import torch
from einops import rearrange
def npu_sdpa_attention(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
seq_len_info_q=None,
seq_len_info_kv=None,
origin_attn_mask: torch.Tensor = None,
dropout_p: float = 0.0,
scale: float = 1.0,
causal=None,
padded=None,
):
"""
The scaled dot product attention.
Arguments:
q: (batch, q_seqlen, nheads, headdim)
k: (batch, kv_seqlen, nheads, headdim)
v: (batch, kv_seqlen, nheads, headdim)
batch_size: int.
seq_len: int.
dropout_p: float. Dropout probability.
scale: float. The scaling of QK^T before applying softmax.
Default to 1.
Return:
attn_out: (batch, q_seqlen, nheads, headdim).
"""
q, k, v = [rearrange(x, "b s h d -> b h s d").contiguous() for x in (q, k, v)]
output = torch.nn.functional.scaled_dot_product_attention(
q,
k,
v,
attn_mask=origin_attn_mask,
dropout_p=dropout_p,
is_causal=origin_attn_mask is None,
scale=scale,
)
output = rearrange(output, "b h s d -> b s (h d)")
return output
return npu_sdpa_attention