Update llama.py
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1 changed files with 4 additions and 118 deletions
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@ -72,122 +72,7 @@ pass
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from math import sqrt as math_sqrt
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def _LlamaAttention_fast_forward_inference(
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self,
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hidden_states: torch.Tensor,
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past_key_value: Optional[Tuple[torch.Tensor]],
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position_ids,
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):
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"""
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https://github.com/huggingface/transformers/blob/main/src/transformers/models/llama/modeling_llama.py#L406
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Fast inference using KV cache.
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QK^T can be computed in 4 chunks
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[Q, q] @ [K, k].T where q, k are the new tokens.
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[QK^T, Qk^T]
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[qK^T, qk^T]
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Since the attention mask wipes Qk^T, we just get
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[QK^T, 0]
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[qK^T, qk^T]
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Since softmax is row-wise, we get
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softmax([QK^T, 0])
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softmax([qK^T, qk^T])
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We then multiply by [V]
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[v]
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softmax([QK^T, 0]) [softmax(QK^T)V] *
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softmax([qK^T, qk^T]) [softmax([qK^T, qk^T]) @ [V, v]]
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But notice * [softmax(QK^T)V] is just the last attention.
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We just need to compute the last final row.
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This means we can pass in a row of Q, but we need to
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remember K and V, which are called the KV cache.
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"""
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n_heads = self.num_heads
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n_groups = self.num_key_value_groups
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n_kv_heads = self.num_key_value_heads
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head_dim = self.head_dim
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# assert(n_kv_heads * n_groups == n_heads)
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Xn = hidden_states.view(self.hidden_size)
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K1, V1 = past_key_value
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seq_len = K1.shape[-2]
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K1 = K1.view(n_kv_heads, seq_len, head_dim)
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V1 = V1.view(n_kv_heads, seq_len, head_dim)
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# LoRA or general matrix multiplication
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dtype = Xn.dtype
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# Qn = self.q_proj(Xn)
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# Kn = self.k_proj(Xn)
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# Vn = self.v_proj(Xn)
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Qn = fast_linear_forward(self.q_proj, Xn)
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Kn = fast_linear_forward(self.k_proj, Xn)
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Vn = fast_linear_forward(self.v_proj, Xn)
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# Qn = Qn.view(1, 1, n_heads, head_dim).transpose(1, 2)
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# Kn = Kn.view(1, 1, n_kv_heads, head_dim).transpose(1, 2)
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# Vn = Vn.view(1, 1, n_kv_heads, head_dim).transpose(1, 2)
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Qn = Qn.view(n_heads, 1, head_dim)
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Kn = Kn.view(n_kv_heads, 1, head_dim)
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Vn = Vn.view(n_kv_heads, 1, head_dim)
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# kv_seq_len = K1.shape[-2] + 1
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# cos, sin = self.rotary_emb(Vn, seq_len = kv_seq_len)
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# Qn, Kn = inplace_rope_embedding(Qn, Kn, cos, sin, position_ids)
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cos = self.rotary_emb.cos_cached[seq_len]
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sin = self.rotary_emb.sin_cached[seq_len]
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h = head_dim // 2
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RH_Q = torch.empty((n_heads, 1, head_dim), dtype = dtype, device = "cuda")
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RH_Q[:, :, :h] = Qn[:, :, h:]; RH_Q[:, :, h:] = Qn[:, :, :h]; torch.neg(RH_Q[:, :, :h], out = RH_Q[:, :, :h]);
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Qn *= cos; Qn.addcmul_(RH_Q, sin);
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RH_K = RH_Q[:n_kv_heads, :, :] # torch.empty((n_kv_heads, 1, head_dim), dtype = dtype, device = "cuda")
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RH_K[:, :, :h] = Kn[:, :, h:]; RH_K[:, :, h:] = Kn[:, :, :h]; torch.neg(RH_K[:, :, :h], out = RH_K[:, :, :h]);
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Kn *= cos; Kn.addcmul_(RH_K, sin);
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# New KV cache
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# Kn = torch.cat([K1, Kn], dim = 2)
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# Vn = torch.cat([V1, Vn], dim = 2)
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Kn = torch.cat([K1, Kn], dim = 1)
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Vn = torch.cat([V1, Vn], dim = 1)
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# Grouped query attention
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if n_groups != 1:
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# _, _, cached_len, _ = Kn.shape
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# Knn = Kn[:, :, None, :, :].expand(1, n_kv_heads, n_groups, cached_len, head_dim)
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# Vnn = Vn[:, :, None, :, :].expand(1, n_kv_heads, n_groups, cached_len, head_dim)
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# Knn = Knn.reshape(1, n_heads, cached_len, head_dim)
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# Vnn = Vnn.reshape(1, n_heads, cached_len, head_dim)
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new_seq_len = seq_len + 1
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Knn = Kn[:, None, :, :].expand(n_kv_heads, n_groups, new_seq_len, head_dim)
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Vnn = Vn[:, None, :, :].expand(n_kv_heads, n_groups, new_seq_len, head_dim)
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Knn = Knn.reshape(n_heads, new_seq_len, head_dim)
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Vnn = Vnn.reshape(n_heads, new_seq_len, head_dim)
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else:
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Knn, Vnn = Kn, Vn
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# Attention
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# A = torch.matmul(Qn, Knn.transpose(2, 3))
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A = torch.matmul(Qn, Knn.transpose(1, 2))
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A *= 1.0 / math_sqrt(self.head_dim)
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A[:] = torch.nn.functional.softmax(A, dim = -1, dtype = torch.float32)#.to(A.dtype)
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A = torch.matmul(A, Vnn, out = Qn)
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# A = A.transpose(1, 2)
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A = A.view(self.hidden_size)
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# A = self.o_proj(A)
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A = fast_linear_forward(self.o_proj, A)
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A = A.reshape(1, 1, self.hidden_size)
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# return A, (Kn, Vn)
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return A, (Kn.unsqueeze(0), Vn.unsqueeze(0))
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pass
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@torch.compile
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def LlamaAttention_fast_forward_inference(
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self,
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hidden_states: torch.Tensor,
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@ -236,7 +121,7 @@ def LlamaAttention_fast_forward_inference(
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kv_seq_len = seq_len + 1
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if not hasattr(self, "paged_attention"):
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self.paged_attention = torch.empty((2048, 2, bsz, n_kv_heads, head_dim), dtype = dtype, device = "cuda")
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self.paged_attention = torch.empty((2048+1, 2, bsz, n_kv_heads, head_dim), dtype = dtype, device = "cuda")
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self.paged_attention_K = self.paged_attention[:,0]
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self.paged_attention_V = self.paged_attention[:,1]
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self.paged_attention_K[:seq_len] = K1.permute(2, 0, 1, 3)
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@ -299,6 +184,7 @@ def LlamaAttention_fast_forward_inference(
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pass
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@torch.compile
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def fast_mlp_inference(self, X):
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# gate = self.gate_proj(X)
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# up = self.up_proj(X)
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@ -316,7 +202,7 @@ def fast_mlp_inference(self, X):
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return down
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pass
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@torch.compile
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def fast_rms_layernorm_inference(self, X):
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old_dtype = X.dtype
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XX = X.to(torch.float32)
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