"""Implementation for Gemma3 architecture.""" import dataclasses from typing import Any, Dict, Optional # noqa: UP035 from tvm import tirx from tvm.relax.frontend import nn from tvm.relax.frontend.nn import Tensor, op from mlc_llm import op as op_ext from mlc_llm.model.gemma.gemma_model import GemmaEmbedding from mlc_llm.model.model_utils import index_last_token from mlc_llm.nn import PagedKVCache, RopeMode from mlc_llm.support import logging from mlc_llm.support import tensor_parallel as tp from mlc_llm.support.config import ConfigBase from mlc_llm.support.style import bold logger = logging.getLogger(__name__) @dataclasses.dataclass class Gemma3TextConfig(ConfigBase): """Configuration of the text model inside Gemma3""" # NOTE More fields have defaults due to Huggingface Gemma3 configs missing fields # The defaults for these fields can be found in the transformers library hidden_size: int intermediate_size: int num_hidden_layers: int attention_bias: bool = False num_attention_heads: int = 8 num_key_value_heads: int = 4 head_dim: int = 256 rms_norm_eps: float = 1e-6 hidden_activation: Optional[str] = "gelu_pytorch_tanh" position_embedding_base: int = 1_000_000 rope_scaling: int = 0 context_window_size: int = 131_072 prefill_chunk_size: int = 0 query_pre_attn_scalar: int = 256 sliding_window_size: int = None sliding_window_pattern = 6 kwargs: Dict[str, Any] = dataclasses.field(default_factory=dict) # noqa: UP006 def __post_init__(self): if self.hidden_activation is None: self.hidden_activation = self.kwargs.get("hidden_act", None) if self.sliding_window_size is None: self.sliding_window_size = self.kwargs.get("sliding_window", None) if self.hidden_activation not in ("gelu", "gelu_pytorch_tanh"): raise ValueError("Only GeLU is supported as the activation for gemma.") if self.attention_bias: raise ValueError('Only "False" attention_bias is supported for gemma') if self.position_embedding_base == 1000000 and "rope_theta" in self.kwargs: self.position_embedding_base = self.kwargs.pop("rope_theta") if self.context_window_size == 0: for name in ["max_position_embeddings", "max_sequence_length"]: if name in self.kwargs: self.context_window_size = self.kwargs.pop(name) logger.info( "%s not found in config.json. Falling back to %s (%d)", bold("context_window_size"), bold(name), self.context_window_size, ) break else: raise ValueError( "Unable to determine the maximum sequence length, because none of " "`context_window_size`, `max_position_embeddings` or `max_sequence_length` is " "provided in `config.json`." ) assert self.num_attention_heads % self.num_key_value_heads == 0 if self.prefill_chunk_size == 0: logger.info( "%s defaults to %d", bold("prefill_chunk_size"), min(self.context_window_size, 8192), ) self.prefill_chunk_size = min(self.context_window_size, 8192) elif self.prefill_chunk_size > self.context_window_size: logger.info( "Overriding %s from %d to %d", bold("prefill_chunk_size"), self.prefill_chunk_size, min(self.context_window_size, 8192), ) self.prefill_chunk_size = min(self.context_window_size, 8192) # NOTE: override the context window size with the Gemma2 sliding window size, # as the sliding window attention every other layer is yet to be supported. self.context_window_size = max(self.sliding_window_size, 8192) @dataclasses.dataclass class Gemma3Config(ConfigBase): """Configuration of the Gemma3 model""" text_config: Gemma3TextConfig = None vocab_size: int = 262_208 tensor_parallel_shards: int = 1 max_batch_size: int = 1 context_window_size: int = -1 sliding_window_size: int = -1 prefill_chunk_size: int = -1 is_text_model: bool = False kwargs: Dict[str, Any] = dataclasses.field(default_factory=dict) # noqa: UP006 def __post_init__(self): if self.text_config is None: self.is_text_model = True self.text_config = Gemma3TextConfig.from_dict(self.kwargs) text_config_dict: Dict[str, Any] # noqa: UP006 if isinstance(self.text_config, Gemma3TextConfig): text_config_dict = dataclasses.asdict(self.text_config) else: text_config_dict = dict(self.text_config) for k, v in text_config_dict.pop("kwargs", {}).items(): text_config_dict[k] = v self.text_config = Gemma3TextConfig.from_dict(text_config_dict) for k in ["context_window_size", "prefill_chunk_size", "sliding_window_size"]: if getattr(self, k) <= 0: if hasattr(self.text_config, k): setattr(self, k, getattr(self.text_config, k)) class Gemma3MLP(nn.Module): def __init__(self, config: Gemma3Config): super().__init__() if config.text_config.intermediate_size % config.tensor_parallel_shards != 0: raise ValueError( f"Cannot split MLP intermediate size {config.text_config.intermediate_size} " f"evenly to {config.tensor_parallel_shards} GPUs." ) self.intermediate_size = ( config.text_config.intermediate_size // config.tensor_parallel_shards ) self.gate_up_proj = nn.Linear( in_features=config.text_config.hidden_size, out_features=2 * self.intermediate_size, bias=False, ) self.down_proj = nn.Linear( self.intermediate_size, config.text_config.hidden_size, bias=False ) def forward(self, x: Tensor): concat_x1_x2 = self.gate_up_proj(x) x1, x2 = op.split(concat_x1_x2, 2, axis=-1) return self.down_proj(op.gelu(x1, approximate="tanh") * x2) class Gemma3Attention(nn.Module): def __init__(self, config: Gemma3Config): self.head_dim = config.text_config.head_dim self.num_q_heads = config.text_config.num_attention_heads // config.tensor_parallel_shards self.num_kv_heads = config.text_config.num_key_value_heads assert self.num_kv_heads % config.tensor_parallel_shards == 0, ( f"num_kv_heads({self.num_kv_heads}) must be divisible by tensor_parallel_shards" ) assert self.num_kv_heads >= config.tensor_parallel_shards, ( f"Too large tensor_parallel_shards, must be smaller than {self.num_kv_heads}" ) self.num_kv_heads = self.num_kv_heads // config.tensor_parallel_shards self.q_proj = nn.Linear( in_features=config.text_config.hidden_size, out_features=self.num_q_heads * self.head_dim, bias=config.text_config.attention_bias, ) self.k_proj = nn.Linear( in_features=config.text_config.hidden_size, out_features=self.num_kv_heads * self.head_dim, bias=config.text_config.attention_bias, ) self.v_proj = nn.Linear( in_features=config.text_config.hidden_size, out_features=self.num_kv_heads * self.head_dim, bias=config.text_config.attention_bias, ) self.o_proj = nn.Linear( in_features=self.num_q_heads * self.head_dim, out_features=config.text_config.hidden_size, bias=config.text_config.attention_bias, ) self.q_norm = nn.RMSNorm( config.text_config.head_dim, -1, config.text_config.rms_norm_eps, bias=False ) self.k_norm = nn.RMSNorm( config.text_config.head_dim, -1, config.text_config.rms_norm_eps, bias=False ) # self.scaling_factor = (self.head_dim / config.text_config.query_pre_attn_scalar) ** 0.5 self.scaling = config.text_config.query_pre_attn_scalar**-0.5 def forward(self, hidden_states: Tensor, paged_kv_cache: PagedKVCache, layer_id: int): d, h_q = self.head_dim, self.num_q_heads b, s, _ = hidden_states.shape # QKV Projection q_proj = op.reshape(self.q_proj(hidden_states), (b, s, -1, d)) k_proj = op.reshape(self.k_proj(hidden_states), (b, s, -1, d)) v_proj = op.reshape(self.v_proj(hidden_states), (b, s, -1, d)) q_norm = self.q_norm(q_proj) k_norm = self.k_norm(k_proj) qkv = op.concat([q_norm, k_norm, v_proj], dim=2) # Attention output = op.reshape( paged_kv_cache.attention_with_fused_qkv( layer_id, qkv, self.num_q_heads, sm_scale=self.scaling ), (b, s, h_q * d), ) return self.o_proj(output) class Gemma3DecoderLayer(nn.Module): def __init__(self, config: Gemma3Config): rms_norm_eps = config.text_config.rms_norm_eps self.self_attn = Gemma3Attention(config) self.mlp = Gemma3MLP(config) # Gemma RMSNorm adds 1 to the weights. It is already fused in the loader self.input_layernorm = nn.RMSNorm( config.text_config.hidden_size, -1, rms_norm_eps, bias=False ) self.post_attention_layernorm = nn.RMSNorm( config.text_config.hidden_size, -1, rms_norm_eps, bias=False ) self.pre_feedforward_layernorm = nn.RMSNorm( config.text_config.hidden_size, -1, rms_norm_eps, bias=False ) self.post_feedforward_layernorm = nn.RMSNorm( config.text_config.hidden_size, -1, rms_norm_eps, bias=False ) def _set_tp(): def _set(layer, hint): layer.weight.attrs["shard_strategy"] = hint i = self.mlp.intermediate_size _set(self.self_attn.q_proj, tp.ShardSingleDim("_shard_q", dim=0)) _set(self.self_attn.k_proj, tp.ShardSingleDim("_shard_k", dim=0)) _set(self.self_attn.v_proj, tp.ShardSingleDim("_shard_v", dim=0)) _set(self.self_attn.q_norm, tp.ShardSingleDim("_shard_q_norm", dim=0)) _set(self.self_attn.k_norm, tp.ShardSingleDim("_shard_k_norm", dim=0)) _set(self.self_attn.o_proj, tp.ShardSingleDim("_shard_o", dim=1)) _set( self.mlp.gate_up_proj, tp.ShardSingleDim("_shard_mlp_up", segs=[i, i], dim=0), ) _set(self.mlp.down_proj, tp.ShardSingleDim("_shard_mlp_down", dim=1)) self.tensor_parallel_shards = config.tensor_parallel_shards _set_tp() def forward(self, hidden_states: Tensor, paged_kv_cache: PagedKVCache, layer_id: int): out = self.self_attn(self.input_layernorm(hidden_states), paged_kv_cache, layer_id) out = self._apply_post_matmul_norm(out, norm=self.post_attention_layernorm) hidden_states = out + hidden_states out = self.pre_feedforward_layernorm(hidden_states) out = self.mlp(out) out = self._apply_post_matmul_norm(out, norm=self.post_feedforward_layernorm) hidden_states = out + hidden_states return hidden_states def _apply_post_matmul_norm(self, out: Tensor, norm: nn.Tensor): if self.tensor_parallel_shards > 1: return norm(op.ccl_allreduce(out, "sum")) return norm(out) class Gemma3TextModel(nn.Module): def __init__(self, config: Gemma3Config): self.hidden_size = config.text_config.hidden_size assert config.text_config.hidden_size % config.text_config.num_attention_heads == 0 self.embed_tokens = GemmaEmbedding("vocab_size", config.text_config.hidden_size) self.layers = nn.ModuleList( [Gemma3DecoderLayer(config) for _ in range(config.text_config.num_hidden_layers)] ) self.norm = nn.RMSNorm( config.text_config.hidden_size, -1, config.text_config.rms_norm_eps, bias=False, ) def forward(self, input_embed: Tensor, paged_kv_cache: PagedKVCache): hidden_states = input_embed hidden_states = hidden_states * (self.hidden_size**0.5) for layer_id, layer in enumerate(self.layers): hidden_states = layer(hidden_states, paged_kv_cache, layer_id) hidden_states = self.norm(hidden_states) return hidden_states class Gemma3LanguageModel(nn.Module): def __init__(self, config: Gemma3Config): self.model = Gemma3TextModel(config) self.config = config self.num_hidden_layers = config.text_config.num_hidden_layers self.num_attention_heads = config.text_config.num_attention_heads self.num_key_value_heads = config.text_config.num_key_value_heads self.head_dim = config.text_config.head_dim self.hidden_size = config.text_config.hidden_size self.vocab_size = config.vocab_size self.rope_theta = config.text_config.position_embedding_base self.rope_scaling = config.text_config.rope_scaling self.tensor_parallel_shards = config.tensor_parallel_shards self.dtype = "float32" def to(self, dtype: Optional[str] = None): super().to(dtype=dtype) if dtype is not None: self.dtype = dtype def get_logits(self, hidden_states: Tensor): logits = self.model.embed_tokens.lm_head_forward(hidden_states) if logits.dtype != "float32": logits = logits.astype("float32") return logits def batch_forward( self, input_embeds: Tensor, paged_kv_cache: PagedKVCache, logit_positions: Optional[Tensor] = None, ): op_ext.configure() hidden_states = self.model(input_embeds, paged_kv_cache) if logit_positions is not None: hidden_states = op.take(hidden_states, logit_positions, axis=1) logits = self.get_logits(hidden_states) return logits def embed(self, input_ids: Tensor): if self.tensor_parallel_shards > 1: input_ids = op.ccl_broadcast_from_worker0(input_ids) return self.model.embed_tokens(input_ids) def prefill(self, input_embed: Tensor, paged_kv_cache: PagedKVCache): op_ext.configure() hidden_states = self.model(input_embed, paged_kv_cache) hidden_states = index_last_token(hidden_states) logits = self.get_logits(hidden_states) return logits, paged_kv_cache def decode(self, input_embed: Tensor, paged_kv_cache: PagedKVCache): op_ext.configure() hidden_states = self.model(input_embed, paged_kv_cache) logits = self.get_logits(hidden_states) return logits, paged_kv_cache def batch_prefill( self, input_embeds: Tensor, logit_positions: Tensor, paged_kv_cache: PagedKVCache, ): if self.tensor_parallel_shards > 1: logit_positions = op.ccl_broadcast_from_worker0(logit_positions) logits = self.batch_forward(input_embeds, paged_kv_cache, logit_positions) return logits, paged_kv_cache def batch_decode(self, input_embeds: Tensor, paged_kv_cache: PagedKVCache): logits = self.batch_forward(input_embeds, paged_kv_cache) return logits, paged_kv_cache def batch_verify(self, input_embeds: Tensor, paged_kv_cache: PagedKVCache): logits = self.batch_forward(input_embeds, paged_kv_cache) return logits, paged_kv_cache def create_paged_kv_cache( self, max_batch_size: tirx.Var, max_total_seq_len: tirx.Var, prefill_chunk_size: tirx.Var, page_size: tirx.Var, support_sliding_window: tirx.Var, ) -> PagedKVCache: # if "factor" in self.rope_scaling: # rope_scaling = self.rope_scaling["factor"] # else: # rope_scaling = 1 return PagedKVCache.create_generic( attn_kind=[ ( "mha_sliding" if ((i + 1) % self.config.text_config.sliding_window_pattern) else "mha" ) for i in range(self.num_hidden_layers) ], max_batch_size=max_batch_size, max_total_seq_len=max_total_seq_len, prefill_chunk_size=prefill_chunk_size, page_size=page_size, support_sliding_window=support_sliding_window, num_hidden_layers=self.num_hidden_layers, num_attention_heads=self.num_attention_heads // self.tensor_parallel_shards, num_key_value_heads=self.num_key_value_heads // self.tensor_parallel_shards, qk_head_dim=self.head_dim, v_head_dim=self.head_dim, rope_mode=RopeMode.NORMAL, rope_scale=1, rope_theta=self.rope_theta, dtype=self.dtype, ) def get_default_spec(self): mod_spec = { "embed": { "input_ids": nn.spec.Tensor(["seq_len"], "int32"), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "prefill": { "input_embed": nn.spec.Tensor([1, "seq_len", self.hidden_size], self.dtype), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "decode": { "input_embed": nn.spec.Tensor([1, 1, self.hidden_size], self.dtype), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_prefill": { "input_embeds": nn.spec.Tensor([1, "seq_len", self.hidden_size], self.dtype), "logit_positions": nn.spec.Tensor(["batch_size"], "int32"), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_decode": { "input_embeds": nn.spec.Tensor(["batch_size", 1, self.hidden_size], self.dtype), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_verify": { "input_embeds": nn.spec.Tensor([1, "seq_len", self.hidden_size], self.dtype), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "create_paged_kv_cache": { "max_batch_size": int, "max_total_seq_len": int, "prefill_chunk_size": int, "page_size": int, "support_sliding_window": int, "$": { "param_mode": "none", "effect_mode": "none", }, }, } return nn.spec.ModuleSpec.from_raw(mod_spec, self) class Gemma3ForCausalLM(nn.Module): def __init__(self, config: Gemma3Config): super().__init__() self.config = config self.language_model = Gemma3LanguageModel(config) self.vocab_size = config.vocab_size self.dtype = "float32" self.tensor_parallel_shards = config.tensor_parallel_shards def to(self, dtype: Optional[str] = None): super().to(dtype=dtype) self.language_model.to(dtype=dtype) if dtype is not None: self.dtype = dtype def get_logits(self, hidden_states: Tensor): logits = self.language_model.model.embed_tokens.lm_head_forward(hidden_states) if logits.dtype != "float32": logits = logits.astype("float32") return logits def batch_forward( self, input_embeds: Tensor, paged_kv_cache: PagedKVCache, logit_positions: Optional[Tensor] = None, ): op_ext.configure() hidden_states = self.language_model.model(input_embeds, paged_kv_cache) if logit_positions is not None: hidden_states = op.take(hidden_states, logit_positions, axis=1) logits = self.get_logits(hidden_states) return logits def embed(self, input_ids: Tensor): if self.tensor_parallel_shards > 1: input_ids = op.ccl_broadcast_from_worker0(input_ids) return self.language_model.model.embed_tokens(input_ids) def prefill(self, input_embed: Tensor, paged_kv_cache: PagedKVCache): op_ext.configure() hidden_states = self.language_model.model(input_embed, paged_kv_cache) hidden_states = index_last_token(hidden_states) logits = self.get_logits(hidden_states) return logits, paged_kv_cache def decode(self, input_embed: Tensor, paged_kv_cache: PagedKVCache): op_ext.configure() hidden_states = self.language_model.model(input_embed, paged_kv_cache) logits = self.get_logits(hidden_states) return logits, paged_kv_cache def batch_prefill( self, input_embeds: Tensor, logit_positions: Tensor, paged_kv_cache: PagedKVCache, ): if self.tensor_parallel_shards > 1: logit_positions = op.ccl_broadcast_from_worker0(logit_positions) logits = self.batch_forward(input_embeds, paged_kv_cache, logit_positions) return logits, paged_kv_cache def batch_decode(self, input_embeds: Tensor, paged_kv_cache: PagedKVCache): logits = self.batch_forward(input_embeds, paged_kv_cache) return logits, paged_kv_cache def batch_verify(self, input_embeds: Tensor, paged_kv_cache: PagedKVCache): logits = self.batch_forward(input_embeds, paged_kv_cache) return logits, paged_kv_cache def create_paged_kv_cache( self, max_batch_size: tirx.Var, max_total_seq_len: tirx.Var, prefill_chunk_size: tirx.Var, page_size: tirx.Var, support_sliding_window: tirx.Var, ) -> PagedKVCache: # if "factor" in self.language_model.rope_scaling: # rope_scaling = self.language_model.rope_scaling["factor"] # else: # rope_scaling = 1 return PagedKVCache.create_generic( attn_kind=[ ( "mha_sliding" if ((i + 1) % self.config.text_config.sliding_window_pattern) else "mha" ) for i in range(self.language_model.num_hidden_layers) ], max_batch_size=max_batch_size, max_total_seq_len=max_total_seq_len, prefill_chunk_size=prefill_chunk_size, page_size=page_size, support_sliding_window=support_sliding_window, num_hidden_layers=self.language_model.num_hidden_layers, num_attention_heads=self.language_model.num_attention_heads // self.tensor_parallel_shards, num_key_value_heads=self.language_model.num_key_value_heads // self.tensor_parallel_shards, qk_head_dim=self.language_model.head_dim, v_head_dim=self.language_model.head_dim, rope_mode=RopeMode.NORMAL, rope_scale=1, rope_theta=self.language_model.rope_theta, dtype=self.dtype, ) def get_default_spec(self): mod_spec = { "embed": { "input_ids": nn.spec.Tensor(["seq_len"], "int32"), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "prefill": { "input_embed": nn.spec.Tensor( [1, "seq_len", self.language_model.hidden_size], self.dtype ), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "decode": { "input_embed": nn.spec.Tensor([1, 1, self.language_model.hidden_size], self.dtype), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_prefill": { "input_embeds": nn.spec.Tensor( [1, "seq_len", self.language_model.hidden_size], self.dtype ), "logit_positions": nn.spec.Tensor(["batch_size"], "int32"), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_decode": { "input_embeds": nn.spec.Tensor( ["batch_size", 1, self.language_model.hidden_size], self.dtype ), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "batch_verify": { "input_embeds": nn.spec.Tensor( [1, "seq_len", self.language_model.hidden_size], self.dtype ), "paged_kv_cache": nn.spec.Object(object_type=PagedKVCache), "$": { "param_mode": "packed", "effect_mode": "none", }, }, "create_paged_kv_cache": { "max_batch_size": int, "max_total_seq_len": int, "prefill_chunk_size": int, "page_size": int, "support_sliding_window": int, "$": { "param_mode": "none", "effect_mode": "none", }, }, } return nn.spec.ModuleSpec.from_raw(mod_spec, self)