180 lines
7.2 KiB
Python
180 lines
7.2 KiB
Python
import math
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import torch
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import torch.nn as nn
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from torch.nn import functional as F
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from transformers.models.llama.modeling_llama import LlamaAttention, apply_rotary_pos_emb
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from ._fused_base import FusedBaseAttentionModule
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from ..utils.import_utils import compare_pytorch_version, dynamically_import_QuantLinear
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class FusedLlamaAttentionForQuantizedModel(FusedBaseAttentionModule):
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"""Multi-headed attention from 'Attention Is All You Need' paper"""
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def __init__(
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self,
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hidden_size,
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num_heads,
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qkv_proj,
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o_proj,
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rotary_emb,
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):
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super().__init__()
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self.hidden_size = hidden_size
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self.num_heads = num_heads
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self.head_dim = hidden_size // num_heads
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if self.head_dim * num_heads != self.hidden_size:
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raise ValueError(
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f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
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f" and `num_heads`: {num_heads})."
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)
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self.qkv_proj = qkv_proj
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self.o_proj = o_proj
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self.rotary_emb = rotary_emb
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def _shape(self, tensor, seq_len, bsz):
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return tensor.view(bsz, seq_len, self.num_heads, self.head_dim).transpose(1, 2).contiguous()
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def forward(
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self,
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hidden_states,
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past_key_value=None,
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attention_mask=None,
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position_ids=None,
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output_attentions=False,
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use_cache=False,
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**kwargs
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):
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"""Input shape: Batch x Time x Channel"""
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bsz, q_len, _ = hidden_states.size()
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qkv_states = self.qkv_proj(hidden_states)
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query_states, key_states, value_states = torch.split(qkv_states, self.hidden_size, dim=2)
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query_states = query_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
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key_states = key_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
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value_states = value_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
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kv_seq_len = key_states.shape[-2]
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if past_key_value is not None:
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kv_seq_len += past_key_value[0].shape[-2]
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cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)
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query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_ids)
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# [bsz, nh, t, hd]
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is_causal = past_key_value is None
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if past_key_value is not None:
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# reuse k, v, self_attention
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key_states = torch.cat([past_key_value[0], key_states], dim=2)
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value_states = torch.cat([past_key_value[1], value_states], dim=2)
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if use_cache:
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# Since qkv_proj is fused, query_states etc will hold a reference to the original qkv_states tensor
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# which can cause excessive memory usage by the cache. `contiguous` is a convenient way to workaround this.
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query_states = query_states.contiguous()
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key_states = key_states.contiguous()
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value_states = value_states.contiguous()
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past_key_value = (key_states, value_states) if use_cache else None
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if compare_pytorch_version("v2.0.0", op="eq"):
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attn_output = F.scaled_dot_product_attention(
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query_states,
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key_states,
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value_states,
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attn_mask=None if is_causal else attention_mask,
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is_causal=is_causal
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)
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attn_weights = None
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else:
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attn_weights = torch.matmul(query_states, key_states.transpose(2, 3)) / math.sqrt(self.head_dim)
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if attn_weights.size() != (bsz, self.num_heads, q_len, kv_seq_len):
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raise ValueError(
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f"Attention weights should be of size {(bsz * self.num_heads, q_len, kv_seq_len)}, but is"
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f" {attn_weights.size()}"
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)
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if attention_mask is not None:
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if attention_mask.size() != (bsz, 1, q_len, kv_seq_len):
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raise ValueError(
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f"Attention mask should be of size {(bsz, 1, q_len, kv_seq_len)}, but is {attention_mask.size()}"
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)
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attn_weights = attn_weights + attention_mask
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attn_weights = torch.max(attn_weights, torch.tensor(torch.finfo(attn_weights.dtype).min))
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# upcast attention to fp32
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attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query_states.dtype)
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attn_output = torch.matmul(attn_weights, value_states)
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if attn_output.size() != (bsz, self.num_heads, q_len, self.head_dim):
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raise ValueError(
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f"`attn_output` should be of size {(bsz, self.num_heads, q_len, self.head_dim)}, but is"
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f" {attn_output.size()}"
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)
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attn_output = attn_output.transpose(1, 2)
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attn_output = attn_output.reshape(bsz, q_len, self.hidden_size)
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attn_output = self.o_proj(attn_output)
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if not output_attentions:
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attn_weights = None
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return attn_output, attn_weights, past_key_value
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@classmethod
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def inject_to_model(cls, model, use_triton=False, group_size=-1, use_cuda_fp16=True, desc_act=False, **kwargs):
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"""
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Replace all LlamaAttention modules with QuantLlamaAttention modules, fusing the q, k, v projections.
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"""
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QuantLinear = dynamically_import_QuantLinear(use_triton=use_triton, desc_act=desc_act, group_size=group_size)
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for name, m in model.named_modules():
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if not isinstance(m, LlamaAttention):
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continue
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q_proj = m.q_proj
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k_proj = m.k_proj
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v_proj = m.v_proj
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qweights = torch.cat([q_proj.qweight, k_proj.qweight, v_proj.qweight], dim=1)
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qzeros = torch.cat([q_proj.qzeros, k_proj.qzeros, v_proj.qzeros], dim=1)
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scales = torch.cat([q_proj.scales, k_proj.scales, v_proj.scales], dim=1)
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g_idx = torch.cat([q_proj.g_idx, k_proj.g_idx, v_proj.g_idx], dim=0)
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bias = torch.cat([q_proj.bias, k_proj.bias, v_proj.bias], dim=0) if q_proj.bias is not None else None
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qlinear_args = (
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q_proj.bits,
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q_proj.group_size,
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q_proj.infeatures,
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q_proj.outfeatures + k_proj.outfeatures + v_proj.outfeatures,
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True if q_proj.bias is not None else False,
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)
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qlinear_kwargs = dict()
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if (not desc_act or group_size == -1) and not use_triton:
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qlinear_kwargs["use_cuda_fp16"] = use_cuda_fp16
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qkv_layer = QuantLinear(*qlinear_args, **qlinear_kwargs)
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qkv_layer.qweight = qweights
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qkv_layer.qzeros = qzeros
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qkv_layer.scales = scales
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qkv_layer.g_idx = g_idx
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qkv_layer.bias = bias
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attn = cls(m.hidden_size, m.num_heads, qkv_layer, m.o_proj, m.rotary_emb)
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if '.' in name:
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parent_name = name.rsplit('.', 1)[0]
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child_name = name[len(parent_name) + 1:]
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parent = model.get_submodule(parent_name)
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else:
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parent_name = ''
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parent = model
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child_name = name
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setattr(parent, child_name, attn)
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__all__ = ["FusedLlamaAttentionForQuantizedModel"]
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