提交vllm0.11.0开发分支

vllm_kunlun/ops/fla/torch_fla.py

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+import torch 
+import torch.nn.functional as F
+def l2norm(x: torch.FloatTensor, dim: int = -1, eps: float = 1e-6):
+    """This function is intended to align with the l2norm implementation in the FLA library."""
+    inv_norm = torch.rsqrt((x * x).sum(dim=dim, keepdim=True) + eps)
+    return x * inv_norm
+
+def torch_chunk_gated_delta_rule(
+    query,
+    key,
+    value,
+    g,
+    beta,
+    chunk_size=64,
+    initial_state=None,
+    output_final_state=False,
+    use_qk_l2norm_in_kernel=False,
+):
+    initial_dtype = query.dtype
+    if use_qk_l2norm_in_kernel:
+        query = l2norm(query, dim=-1, eps=1e-6)
+        key = l2norm(key, dim=-1, eps=1e-6)
+    query, key, value, beta, g = [
+        x.transpose(1, 2).contiguous().to(torch.float32) for x in (query, key, value, beta, g)
+    ]
+
+    batch_size, num_heads, sequence_length, k_head_dim = key.shape
+    v_head_dim = value.shape[-1]
+    pad_size = (chunk_size - sequence_length % chunk_size) % chunk_size
+    query = F.pad(query, (0, 0, 0, pad_size))
+    key = F.pad(key, (0, 0, 0, pad_size))
+    value = F.pad(value, (0, 0, 0, pad_size))
+    beta = F.pad(beta, (0, pad_size))
+    g = F.pad(g, (0, pad_size))
+    total_sequence_length = sequence_length + pad_size
+    scale = 1 / (query.shape[-1] ** 0.5)
+    query = query * scale
+
+    v_beta = value * beta.unsqueeze(-1)
+    k_beta = key * beta.unsqueeze(-1)
+    # reshape to chunks
+    query, key, value, k_beta, v_beta = [
+        x.reshape(x.shape[0], x.shape[1], -1, chunk_size, x.shape[-1]) for x in (query, key, value, k_beta, v_beta)
+    ]
+    g = g.reshape(g.shape[0], g.shape[1], -1, chunk_size)
+    mask = torch.triu(torch.ones(chunk_size, chunk_size, dtype=torch.bool, device=query.device), diagonal=0)
+
+    # chunk decay
+    g = g.cumsum(dim=-1)
+    decay_mask = ((g.unsqueeze(-1) - g.unsqueeze(-2)).tril().exp().float()).tril()
+    attn = -((k_beta @ key.transpose(-1, -2)) * decay_mask).masked_fill(mask, 0)
+    for i in range(1, chunk_size):
+        row = attn[..., i, :i].clone()
+        sub = attn[..., :i, :i].clone()
+        attn[..., i, :i] = row + (row.unsqueeze(-1) * sub).sum(-2)
+    attn = attn + torch.eye(chunk_size, dtype=attn.dtype, device=attn.device)
+    value = attn @ v_beta
+    k_cumdecay = attn @ (k_beta * g.exp().unsqueeze(-1))
+    last_recurrent_state = (
+        torch.zeros(batch_size, num_heads, k_head_dim, v_head_dim).to(value)
+        if initial_state is None
+        else initial_state.to(value)
+    )
+    core_attn_out = torch.zeros_like(value)
+    mask = torch.triu(torch.ones(chunk_size, chunk_size, dtype=torch.bool, device=query.device), diagonal=1)
+
+    # for each chunk
+    for i in range(0, total_sequence_length // chunk_size):
+        q_i, k_i, v_i = query[:, :, i], key[:, :, i], value[:, :, i]
+        attn = (q_i @ k_i.transpose(-1, -2) * decay_mask[:, :, i]).masked_fill_(mask, 0)
+        v_prime = (k_cumdecay[:, :, i]) @ last_recurrent_state
+        v_new = v_i - v_prime
+        attn_inter = (q_i * g[:, :, i, :, None].exp()) @ last_recurrent_state
+        core_attn_out[:, :, i] = attn_inter + attn @ v_new
+        last_recurrent_state = (
+            last_recurrent_state * g[:, :, i, -1, None, None].exp()
+            + (k_i * (g[:, :, i, -1, None] - g[:, :, i]).exp()[..., None]).transpose(-1, -2) @ v_new
+        )
+
+    if not output_final_state:
+        last_recurrent_state = None
+    core_attn_out = core_attn_out.reshape(core_attn_out.shape[0], core_attn_out.shape[1], -1, core_attn_out.shape[-1])
+    core_attn_out = core_attn_out[:, :, :sequence_length]
+    core_attn_out = core_attn_out.transpose(1, 2).contiguous().to(initial_dtype)
+    return core_attn_out, last_recurrent_state