import torch from vllm.config import get_current_vllm_config from vllm.distributed import get_tensor_model_parallel_rank, get_tensor_model_parallel_world_size from vllm.logger import logger from vllm_ascend.utils import AscendDeviceType, get_ascend_device_type from .base import AscendAttentionScheme from .registry import register_scheme def _fa_quant_weight_loader(param: torch.Tensor, loaded_weight: torch.Tensor): """Weight loader for MLA-based C8 (FAKQuant) models.""" if param.numel() == 1 and loaded_weight.numel() == 1: param.data.fill_(loaded_weight.item()) else: tp_rank = get_tensor_model_parallel_rank() tp_size = get_tensor_model_parallel_world_size() shard_size = loaded_weight.shape[0] // tp_size loaded_weight = loaded_weight.narrow(0, shard_size * tp_rank, shard_size) assert param.size() == loaded_weight.size(), ( "[vllm-ascend/FAKQuant] Attempted to load weight " f"({loaded_weight.size()}) into parameter ({param.size()}) " f"when TP size is {tp_size} and TP rank is {tp_rank}." ) param.data.copy_(loaded_weight) @register_scheme("FAKQuant", "attention") class AscendFAQuantAttentionMethod: def __init__(self): vllm_config = get_current_vllm_config() config = vllm_config.model_config.hf_config self.kv_lora_rank = getattr(config, "kv_lora_rank", 0) self.qk_rope_head_dim = getattr(config, "qk_rope_head_dim", 0) def create_weights(self, layer: torch.nn.Module) -> None: extra_module_names = ["fa_q", "fa_k", "fa_v"] for name in extra_module_names: setattr(layer, name, torch.nn.Module()) params_dict = {} dtype = torch.get_default_dtype() params_dict["fa_q.scale"] = torch.empty((layer.num_heads, 1), dtype=dtype) params_dict["fa_k.scale"] = torch.empty((layer.num_kv_heads, 1), dtype=dtype) params_dict["fa_v.scale"] = torch.empty((layer.num_kv_heads, 1), dtype=dtype) params_dict["fa_q.offset"] = torch.empty((layer.num_heads, 1), dtype=torch.int8) params_dict["fa_k.offset"] = torch.empty((layer.num_kv_heads, 1), dtype=torch.int8) params_dict["fa_v.offset"] = torch.empty((layer.num_kv_heads, 1), dtype=torch.int8) for name, weight in params_dict.items(): module_name, weight_name = name.rsplit(".", 1) module = getattr(layer, module_name) weight_param = torch.nn.Parameter(weight, requires_grad=False) module.register_parameter(weight_name, weight_param) # When loading weights, segment them according to TP weight_param.weight_loader = _fa_quant_weight_loader def process_weights_after_loading(self, layer: torch.nn.Module) -> None: fa_k_scale = torch.squeeze(layer.fa_k.scale).unsqueeze(0) layer.fak_descale_float = torch.nn.Parameter(fa_k_scale.to(torch.float), requires_grad=False) layer.fak_descale = torch.nn.Parameter(fa_k_scale, requires_grad=False) if get_ascend_device_type() == AscendDeviceType.A5: layer.fak_descale_reciprocal = 1.0 / torch.nn.Parameter(fa_k_scale.to(torch.float), requires_grad=False) else: layer.fak_descale_reciprocal = 1.0 / torch.nn.Parameter(fa_k_scale, requires_grad=False) fa_k_offset = torch.squeeze(layer.fa_k.offset).unsqueeze(0) layer.fak_offset = torch.nn.Parameter(fa_k_offset.to(layer.fak_descale.dtype), requires_grad=False) repeated_quant_kscale = fa_k_scale.repeat(self.kv_lora_rank) layer.quant_kscale = repeated_quant_kscale.view(1, self.kv_lora_rank) layer.quant_kscale = 1.0 / torch.nn.Parameter(layer.quant_kscale.to(torch.float), requires_grad=False) @register_scheme("INT8_DYNAMIC", "attention") class AscendSFAQuantAttentionMethod: def __init__(self): vllm_config = get_current_vllm_config() config = vllm_config.model_config.hf_config self.index_head_dim = config.index_head_dim def create_weights(self, layer: torch.nn.Module) -> None: extra_module_names = ["indexer"] for name in extra_module_names: setattr(layer, name, torch.nn.Module()) params_dict = {} params_dict["indexer.q_rot"] = torch.empty((self.index_head_dim, self.index_head_dim), dtype=torch.float32) params_dict["indexer.k_rot"] = torch.empty((self.index_head_dim, self.index_head_dim), dtype=torch.float32) for name, weight in params_dict.items(): module_name, weight_name = name.split(".") module = getattr(layer, module_name) weight_param = torch.nn.Parameter(weight, requires_grad=False) module.register_parameter(weight_name, weight_param) def process_weights_after_loading(self, layer: torch.nn.Module) -> None: pass def _c8_kv_scale_weight_loader(param: torch.nn.Parameter, loaded_weight: torch.Tensor) -> None: """Weight loader for dense-attention C8 KV cache scales/offsets.""" loaded_weight = loaded_weight.squeeze() if param.data.shape != loaded_weight.shape: param.data = loaded_weight.to(param.dtype).clone() else: param.data.copy_(loaded_weight) class AscendC8KVCacheAttentionMethod(AscendAttentionScheme): """C8 INT8 KV cache quantization for dense-attention models (e.g. Qwen3).""" def __init__(self, quant_description: dict, prefix: str): self.quant_description = quant_description self.prefix = prefix vllm_config = get_current_vllm_config() self.is_kv_producer = False if vllm_config.kv_transfer_config is not None: self.is_kv_producer = vllm_config.kv_transfer_config.is_kv_producer def create_weights(self, layer: torch.nn.Module) -> None: # Returns int8 if the P node is not a PD detachment node. if not self.is_kv_producer: logger.info_once( "[vllm-ascend/C8_KV] KV cache producer is disabled; setting kv_cache_torch_dtype to torch.int8." ) layer.kv_cache_torch_dtype = torch.int8 # Upgrade impl to the C8-specific subclass so the C8 forward path is always used. if hasattr(layer, "impl"): from vllm_ascend.attention.attention_v1 import AscendC8AttentionBackendImpl layer.impl.__class__ = AscendC8AttentionBackendImpl dtype = torch.get_default_dtype() layer.k_cache_scale = torch.nn.Parameter(torch.ones(1, dtype=dtype), requires_grad=False) layer.k_cache_scale.weight_loader = _c8_kv_scale_weight_loader layer.k_cache_offset = torch.nn.Parameter(torch.zeros(1, dtype=dtype), requires_grad=False) layer.k_cache_offset.weight_loader = _c8_kv_scale_weight_loader layer.v_cache_scale = torch.nn.Parameter(torch.ones(1, dtype=dtype), requires_grad=False) layer.v_cache_scale.weight_loader = _c8_kv_scale_weight_loader layer.v_cache_offset = torch.nn.Parameter(torch.zeros(1, dtype=dtype), requires_grad=False) layer.v_cache_offset.weight_loader = _c8_kv_scale_weight_loader def process_weights_after_loading(self, layer: torch.nn.Module) -> None: layer.k_cache_scale.data = layer.k_cache_scale.data.flatten() layer.k_cache_offset.data = layer.k_cache_offset.data.flatten() layer.v_cache_scale.data = layer.v_cache_scale.data.flatten() layer.v_cache_offset.data = layer.v_cache_offset.data.flatten() def apply( self, layer: torch.nn.Module, query: torch.Tensor, key: torch.Tensor, value: torch.Tensor, kv_cache, attn_metadata, attn_type, scale, output, ) -> torch.Tensor: err_msg = ( "[vllm-ascend/C8_KV] AscendC8KVCacheAttentionMethod.apply should " "not be called. C8 KV cache quantization is handled by the " "attention backend." ) raise RuntimeError(err_msg)