53 lines
1.4 KiB
Python
53 lines
1.4 KiB
Python
from dataclasses import dataclass
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import torch
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from typing import Optional
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@dataclass
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class Seqlen:
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input_lengths: torch.Tensor
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cache_lengths: torch.Tensor
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cu_seqlen_q: Optional[torch.Tensor]
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cu_seqlen_k: Optional[torch.Tensor]
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max_q: int
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max_k: int
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def __init__(
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self,
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input_lengths,
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cache_lengths,
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cu_seqlen_q=None,
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max_q=None,
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max_k=None,
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):
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self.input_lengths = input_lengths
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self.cache_lengths = cache_lengths
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device = self.input_lengths.device
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shape = self.input_lengths.shape
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if cu_seqlen_q is None:
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cu_seqlen_q = torch.arange(
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shape[0] + 1,
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device=device,
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dtype=torch.int32,
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)
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max_q = 1
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else:
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assert max_q is not None
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assert max_k is not None
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cu_seqlen_k = torch.zeros(shape[-1] + 1, device=device, dtype=torch.int32)
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# cuda graphs don't like this and this is necessary to clamp within mistral
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# Although FA2 might not want the clamping
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# cu_seqlen_k[0] = 0
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total = self.input_lengths + self.cache_lengths
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torch.cumsum(total, -1, out=cu_seqlen_k[1:])
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self.cu_seqlen_q = cu_seqlen_q
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self.cu_seqlen_k = cu_seqlen_k
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self.max_q = max_q
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self.max_k = max_k
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def clamp(self, max):
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# Flash decoding doesn't need to clamp
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return self
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