model : MTP support for Mellum2.1 (#30612)

* model : MTP support for Mellum

* model : inline rope construction in Mellum

conversion/mellum.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Iterable, TYPE_CHECKING
+from typing import Callable, Iterable, TYPE_CHECKING
 
 import torch
 
@@ -14,6 +14,54 @@ from .base import ModelBase, TextModel, gguf, logger
 @ModelBase.example("JetBrains/Mellum2-12B-A2.5B-Base")
 class MellumModel(TextModel):
     model_arch = gguf.MODEL_ARCH.MELLUM
+    supports_mtp_export = True
+
+    _n_main_layers: int | None = None
+
+    _experts: list[dict[str, Tensor]] | None = None
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        # number of exported MTP blocks, appended after the trunk layers
+        self.n_nextn = 0 if self.no_mtp else (self.find_hparam(["num_nextn_predict_layers", "num_mtp_layers"], optional=True) or 0)
+        if self.mtp_only and self.n_nextn == 0:
+            raise ValueError("--mtp requested, but the checkpoint has no MTP layers (num_nextn_predict_layers is 0)")
+        if self.n_nextn > 0:
+            if any(t != "sparse" for t in self.hparams.get("mtp_mlp_layer_types") or []):
+                raise ValueError("Mellum MTP layers with dense MLP are not supported")
+            self.block_count += self.n_nextn
+            self.tensor_map = gguf.get_tensor_name_map(self.model_arch, self.block_count)
+
+    def index_tensors(self, remote_hf_model_id: str | None = None):
+        type(self)._n_main_layers = self.hparams["num_hidden_layers"]
+        return super().index_tensors(remote_hf_model_id=remote_hf_model_id)
+
+    @classmethod
+    def filter_tensors(cls, item: tuple[str, Callable[[], Tensor]]) -> tuple[str, Callable[[], Tensor]] | None:
+        if (titem := super().filter_tensors(item)) is None:
+            return None
+        name, gen = titem
+
+        if name.startswith("mtp."):
+            if cls.no_mtp:
+                return None
+            assert cls._n_main_layers is not None
+            # mtp.layers.{i}.* -> model.layers.{n_main + i}.*, mtp.{fc,norm,...} -> nextn names of the first MTP block
+            remapper = {
+                "fc":                    "eh_proj",
+                "pre_fc_norm_embedding": "enorm",
+                "pre_fc_norm_hidden":    "hnorm",
+                "norm":                  "shared_head.norm",
+            }
+            parts = name.split(".", 3)
+            if len(parts) == 4 and parts[1] == "layers" and parts[2].isdecimal():
+                name = f"model.layers.{cls._n_main_layers + int(parts[2])}.{parts[3]}"
+            elif len(parts) == 3 and parts[1] in remapper:
+                name = f"model.layers.{cls._n_main_layers}.{remapper[parts[1]]}.{parts[2]}"
+        elif cls.mtp_only and name not in ("model.embed_tokens.weight", "model.norm.weight", "lm_head.weight"):
+            return None
+
+        return name, gen
 
     def set_gguf_parameters(self):
         super().set_gguf_parameters()
@@ -26,13 +74,31 @@ class MellumModel(TextModel):
         if (use_sliding_window is True or use_sliding_window is None) and sliding_window is not None:
             self.gguf_writer.add_sliding_window(sliding_window)
             logger.info(f"gguf: sliding window = {sliding_window}")
-            self.gguf_writer.add_sliding_window_pattern([t == "sliding_attention" for t in self.hparams["layer_types"]])
-            logger.info(f"gguf: sliding window pattern length = {len(self.hparams['layer_types'])}")
+            layer_types = list(self.hparams["layer_types"])
+            # MTP blocks default to sliding window attention, as in transformers
+            if self.n_nextn > 0:
+                layer_types += self.hparams.get("mtp_layer_types") or ["sliding_attention"] * self.n_nextn
+            self.gguf_writer.add_sliding_window_pattern([t == "sliding_attention" for t in layer_types])
+            logger.info(f"gguf: sliding window pattern length = {len(layer_types)}")
 
         if (norm_topk_prob := self.hparams.get("norm_topk_prob")) is not None:
             self.gguf_writer.add_expert_weights_norm(norm_topk_prob)
 
-    _experts: list[dict[str, Tensor]] | None = None
+        if self.n_nextn > 0:
+            self.gguf_writer.add_nextn_predict_layers(self.n_nextn)
+
+    def prepare_metadata(self, vocab_only: bool):
+        from_dir = self.fname_out.is_dir()
+        super().prepare_metadata(vocab_only=vocab_only)
+
+        if not self.mtp_only or not from_dir:
+            return
+
+        output_type: str = self.ftype.name.partition("_")[2]
+        fname_default: str = gguf.naming_convention(
+            self.metadata.name, self.metadata.basename, self.metadata.finetune,
+            self.metadata.version, size_label=None, output_type=output_type, model_type=None)
+        self.fname_out = self.fname_out.parent / f"mtp-{fname_default}.gguf"
 
     def modify_tensors(self, data_torch: Tensor, name: str, bid: int | None) -> Iterable[tuple[str, Tensor]]:
         if name.find("experts") != -1:

gguf-py/gguf/constants.py

@@ -5950,6 +5950,11 @@ MODEL_TENSORS: dict[MODEL_ARCH, list[MODEL_TENSOR]] = {
         MODEL_TENSOR.FFN_GATE_EXP,
         MODEL_TENSOR.FFN_DOWN_EXP,
         MODEL_TENSOR.FFN_UP_EXP,
+        # NextN/MTP tensors
+        MODEL_TENSOR.NEXTN_EH_PROJ,
+        MODEL_TENSOR.NEXTN_ENORM,
+        MODEL_TENSOR.NEXTN_HNORM,
+        MODEL_TENSOR.NEXTN_SHARED_HEAD_NORM,
     ],
     MODEL_ARCH.NANBEIGE: [
         MODEL_TENSOR.TOKEN_EMBD,

src/models/mellum.cpp

@@ -29,9 +29,13 @@ void llama_model_mellum::load_arch_hparams(llama_model_loader & ml) {
     }
 }
 
-void llama_model_mellum::load_arch_tensors(llama_model_loader &) {
+void llama_model_mellum::load_arch_tensors(llama_model_loader & ml) {
     LLAMA_LOAD_LOCALS;
 
+    const auto nf          = nextn_flags(ml);
+    const int  trunk_flags = nf.trunk;
+    const int  mtp_flags   = nf.mtp;
+
     tok_embd = create_tensor(tn(LLM_TENSOR_TOKEN_EMBD, "weight"), {n_embd, n_vocab}, 0);
 
     // output
@@ -45,31 +49,56 @@ void llama_model_mellum::load_arch_tensors(llama_model_loader &) {
         throw std::runtime_error("n_expert_used must be > 0 for Mellum");
     }
 
-    for (int i = 0; i < n_layer; ++i) {
+    auto load_block = [&](int i, int flags) {
         auto & layer = layers[i];
 
-        layer.attn_norm = create_tensor(tn(LLM_TENSOR_ATTN_NORM, "weight", i), {n_embd}, 0);
+        layer.attn_norm = create_tensor(tn(LLM_TENSOR_ATTN_NORM, "weight", i), {n_embd}, flags);
 
-        create_tensor_qkv(layer, i, n_embd, n_embd_head_k * n_head, n_embd_gqa, n_embd_gqa, 0);
-        layer.wo = create_tensor(tn(LLM_TENSOR_ATTN_OUT, "weight", i), {n_embd_head_k * n_head, n_embd}, 0);
+        create_tensor_qkv(layer, i, n_embd, n_embd_head_k * n_head, n_embd_gqa, n_embd_gqa, flags);
+        layer.wo = create_tensor(tn(LLM_TENSOR_ATTN_OUT, "weight", i), {n_embd_head_k * n_head, n_embd}, flags);
 
-        layer.attn_k_norm = create_tensor(tn(LLM_TENSOR_ATTN_K_NORM, "weight", i), {n_embd_head_k}, 0);
-        layer.attn_q_norm = create_tensor(tn(LLM_TENSOR_ATTN_Q_NORM, "weight", i), {n_embd_head_k}, 0);
+        layer.attn_k_norm = create_tensor(tn(LLM_TENSOR_ATTN_K_NORM, "weight", i), {n_embd_head_k}, flags);
+        layer.attn_q_norm = create_tensor(tn(LLM_TENSOR_ATTN_Q_NORM, "weight", i), {n_embd_head_k}, flags);
 
-        layer.ffn_norm = create_tensor(tn(LLM_TENSOR_FFN_NORM, "weight", i), {n_embd}, 0);
+        layer.ffn_norm = create_tensor(tn(LLM_TENSOR_FFN_NORM, "weight", i), {n_embd}, flags);
 
-        layer.ffn_gate_inp = create_tensor(tn(LLM_TENSOR_FFN_GATE_INP, "weight", i), {n_embd, n_expert}, 0);
+        layer.ffn_gate_inp = create_tensor(tn(LLM_TENSOR_FFN_GATE_INP, "weight", i), {n_embd, n_expert}, flags);
 
         const int64_t n_ff_exp = hparams.n_ff_exp() ? hparams.n_ff_exp() : n_ff / n_expert_used;
 
-        layer.ffn_gate_exps = create_tensor(tn(LLM_TENSOR_FFN_GATE_EXPS, "weight", i), {  n_embd, n_ff_exp, n_expert}, 0);
-        layer.ffn_down_exps = create_tensor(tn(LLM_TENSOR_FFN_DOWN_EXPS, "weight", i), {n_ff_exp,   n_embd, n_expert}, 0);
-        layer.ffn_up_exps   = create_tensor(tn(LLM_TENSOR_FFN_UP_EXPS,   "weight", i), {  n_embd, n_ff_exp, n_expert}, 0);
+        layer.ffn_gate_exps = create_tensor(tn(LLM_TENSOR_FFN_GATE_EXPS, "weight", i), {  n_embd, n_ff_exp, n_expert}, flags);
+        layer.ffn_down_exps = create_tensor(tn(LLM_TENSOR_FFN_DOWN_EXPS, "weight", i), {n_ff_exp,   n_embd, n_expert}, flags);
+        layer.ffn_up_exps   = create_tensor(tn(LLM_TENSOR_FFN_UP_EXPS,   "weight", i), {  n_embd, n_ff_exp, n_expert}, flags);
+    };
+
+    for (int i = 0; i < n_layer; ++i) {
+        load_block(i, trunk_flags);
+    }
+
+    // MTP block is a regular Mellum decoder block plus the NextN projection and norms
+    for (int i = n_layer; i < n_layer_all; ++i) {
+        auto & layer = layers[i];
+
+        load_block(i, mtp_flags);
+
+        layer.nextn.eh_proj          = create_tensor(tn(LLM_TENSOR_NEXTN_EH_PROJ,          "weight", i), {2 * n_embd, n_embd}, mtp_flags);
+        layer.nextn.enorm            = create_tensor(tn(LLM_TENSOR_NEXTN_ENORM,            "weight", i), {n_embd},             mtp_flags);
+        layer.nextn.hnorm            = create_tensor(tn(LLM_TENSOR_NEXTN_HNORM,            "weight", i), {n_embd},             mtp_flags);
+        layer.nextn.shared_head_norm = create_tensor(tn(LLM_TENSOR_NEXTN_SHARED_HEAD_NORM, "weight", i), {n_embd},             mtp_flags);
     }
 }
 
 std::unique_ptr<llm_graph_context> llama_model_mellum::build_arch_graph(const llm_graph_params & params) const {
-    if (hparams.swa_type == LLAMA_SWA_TYPE_STANDARD) {
+    const bool iswa = hparams.swa_type == LLAMA_SWA_TYPE_STANDARD;
+
+    if (params.gtype == LLM_GRAPH_TYPE_DECODER_MTP) {
+        if (iswa) {
+            return std::make_unique<graph_mtp<true>>(*this, params);
+        }
+        return std::make_unique<graph_mtp<false>>(*this, params);
+    }
+
+    if (iswa) {
         return std::make_unique<graph<true>>(*this, params);
     }
     return std::make_unique<graph<false>>(*this, params);
@@ -151,7 +180,7 @@ llama_model_mellum::graph<iswa>::graph(const llama_model & model, const llm_grap
                     model.layers[il].wo, model.layers[il].wo_b, model.layers[il].wo_s,
                     Qcur, Kcur, Vcur, nullptr, nullptr, nullptr, 1.0f/sqrtf(float(n_embd_head)), il);
         }
-        if (il == n_layer - 1 && inp_out_ids) {
+        if (il == n_layer - 1 && crop_before_nextn(inp_out_ids)) {
             cur   = ggml_get_rows(ctx0,   cur, inp_out_ids);
             inpSA = ggml_get_rows(ctx0, inpSA, inp_out_ids);
         }
@@ -198,6 +227,14 @@ llama_model_mellum::graph<iswa>::graph(const llama_model & model, const llm_grap
             model.output_norm, nullptr,
             LLM_NORM_RMS, -1);
 
+    // post-norm hidden state feeds both the LM head and the MTP head
+    cb(cur, "h_nextn", -1);
+    res->t_h_nextn = cur;
+
+    if (crop_after_nextn(inp_out_ids)) {
+        cur = ggml_get_rows(ctx0, cur, inp_out_ids);
+    }
+
     cb(cur, "result_norm", -1);
     res->t_embd = cur;
 
@@ -208,5 +245,162 @@ llama_model_mellum::graph<iswa>::graph(const llama_model & model, const llm_grap
     res->t_logits = cur;
 }
 
+template <bool iswa>
+llama_model_mellum::graph_mtp<iswa>::graph_mtp(const llama_model & model, const llm_graph_params & params) : llm_graph_context(params) {
+    GGML_ASSERT(hparams.n_layer_nextn == 1 && "MELLUM MTP currently only supports a single MTP block");
+
+    const int64_t n_embd_head = hparams.n_embd_head_v();
+
+    GGML_ASSERT(n_embd_head == hparams.n_embd_head_k());
+    GGML_ASSERT(n_embd_head == n_rot);
+
+    const int il = hparams.n_layer();
+    const auto & layer = model.layers[il];
+
+    GGML_ASSERT(layer.nextn.eh_proj          && "MTP block missing nextn.eh_proj");
+    GGML_ASSERT(layer.nextn.enorm            && "MTP block missing nextn.enorm");
+    GGML_ASSERT(layer.nextn.hnorm            && "MTP block missing nextn.hnorm");
+    GGML_ASSERT(layer.nextn.shared_head_norm && "MTP block missing nextn.shared_head_norm");
+
+    // TODO: extract in a common llm_graph_context::build_inp_embd_h()
+    auto inp = std::make_unique<llm_graph_input_embd_h>(hparams.n_embd_inp(), hparams.n_embd);
+
+    inp->tokens = ggml_new_tensor_1d(ctx0, GGML_TYPE_I32, n_tokens);
+    ggml_set_input(inp->tokens);
+
+    inp->embd = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, hparams.n_embd_inp(), n_tokens);
+    ggml_set_input(inp->embd);
+
+    inp->h = ggml_new_tensor_2d(ctx0, GGML_TYPE_F32, hparams.n_embd, n_tokens);
+    ggml_set_input(inp->h);
+    ggml_set_name(inp->h, "mtp_h_input");
+
+    // TODO: make static using `ggml_build_forward_select()`
+    //       see llm_graph_context::build_inp_embd() for reference
+    ggml_tensor * tok_embd;
+    ASSERT_EMBD_OR_TOKEN(ubatch);
+    if (ubatch.token) {
+        tok_embd = ggml_get_rows(ctx0, model.tok_embd, inp->tokens);
+    } else {
+        tok_embd = inp->embd;
+    }
+    cb(tok_embd, "mtp_tok_embd", il);
+
+    ggml_tensor * h_embd = inp->h;
+
+    res->add_input(std::move(inp));
+
+    ggml_tensor * inp_pos     = build_inp_pos();
+    ggml_tensor * inp_out_ids = build_inp_out_ids();
+
+    using inp_attn_type = std::conditional_t<iswa, llm_graph_input_attn_kv_iswa, llm_graph_input_attn_kv>;
+    inp_attn_type * inp_attn = nullptr;
+
+    if constexpr (iswa) {
+        inp_attn = build_attn_inp_kv_iswa();
+    } else {
+        inp_attn = build_attn_inp_kv();
+    }
+
+    ggml_tensor * e_norm = build_norm(tok_embd, layer.nextn.enorm, nullptr, LLM_NORM_RMS, il);
+    cb(e_norm, "mtp_enorm", il);
+
+    ggml_tensor * h_norm = build_norm(h_embd, layer.nextn.hnorm, nullptr, LLM_NORM_RMS, il);
+    cb(h_norm, "mtp_hnorm", il);
+
+    ggml_tensor * concat = ggml_concat(ctx0, e_norm, h_norm, 0);
+    cb(concat, "mtp_concat", il);
+
+    ggml_tensor * cur = build_lora_mm(layer.nextn.eh_proj, concat, layer.nextn.eh_proj_s);
+    cb(cur, "mtp_eh_proj", il);
+
+    ggml_tensor * inpSA = cur;
+
+    cur = build_norm(cur, layer.attn_norm, nullptr, LLM_NORM_RMS, il);
+    cb(cur, "mtp_attn_norm", il);
+
+    // self_attention
+    {
+        auto [Qcur, Kcur, Vcur] = build_qkv(layer, cur, n_embd_head, n_head, n_head_kv, il);
+
+        Qcur = build_norm(Qcur, layer.attn_q_norm, nullptr, LLM_NORM_RMS, il);
+        cb(Qcur, "mtp_Qcur_normed", il);
+
+        Kcur = build_norm(Kcur, layer.attn_k_norm, nullptr, LLM_NORM_RMS, il);
+        cb(Kcur, "mtp_Kcur_normed", il);
+
+        const bool is_swa = hparams.is_swa(il);
+
+        const float freq_base_l   = model.get_rope_freq_base(cparams, il);
+        const float freq_scale_l  = model.get_rope_freq_scale(cparams, il);
+        const float ext_factor_l  = is_swa ? 0.0f : ext_factor;
+        const float attn_factor_l = is_swa ? 1.0f : attn_factor;
+        const float beta_fast_l   = is_swa ? 32.0f : beta_fast;
+        const float beta_slow_l   = is_swa ? 1.0f  : beta_slow;
+
+        Qcur = ggml_rope_ext(
+            ctx0, Qcur, inp_pos, nullptr,
+            n_rot, rope_type, n_ctx_orig, freq_base_l, freq_scale_l,
+            ext_factor_l, attn_factor_l, beta_fast_l, beta_slow_l
+            );
+
+        Kcur = ggml_rope_ext(
+            ctx0, Kcur, inp_pos, nullptr,
+            n_rot, rope_type, n_ctx_orig, freq_base_l, freq_scale_l,
+            ext_factor_l, attn_factor_l, beta_fast_l, beta_slow_l
+            );
+
+        cb(Qcur, "mtp_Qcur", il);
+        cb(Kcur, "mtp_Kcur", il);
+        cb(Vcur, "mtp_Vcur", il);
+
+        cur = build_attn(inp_attn,
+                layer.wo, layer.wo_b, layer.wo_s,
+                Qcur, Kcur, Vcur, nullptr, nullptr, nullptr, 1.0f/sqrtf(float(n_embd_head)), il);
+        cb(cur, "mtp_attn_out", il);
+    }
+
+    ggml_tensor * ffn_inp = ggml_add(ctx0, cur, inpSA);
+    cb(ffn_inp, "mtp_ffn_inp", il);
+
+    cur = build_norm(ffn_inp, layer.ffn_norm, nullptr, LLM_NORM_RMS, il);
+    cb(cur, "mtp_ffn_norm", il);
+
+    cur = build_moe_ffn(cur,
+            layer.ffn_gate_inp,
+            layer.ffn_up_exps,
+            layer.ffn_gate_exps,
+            layer.ffn_down_exps,
+            nullptr,
+            n_expert, n_expert_used,
+            LLM_FFN_SILU, hparams.expert_weights_norm,
+            hparams.expert_weights_scale,
+            (llama_expert_gating_func_type) hparams.expert_gating_func,
+            il,
+            nullptr, nullptr,
+            layer.ffn_up_exps_s,
+            layer.ffn_gate_exps_s,
+            layer.ffn_down_exps_s);
+    cb(cur, "mtp_ffn_moe_out", il);
+
+    cur = ggml_add(ctx0, cur, ffn_inp);
+    cb(cur, "mtp_ffn_out", il);
+
+    cur = build_norm(cur, layer.nextn.shared_head_norm, nullptr, LLM_NORM_RMS, -1);
+
+    cb(cur, "h_nextn", -1);
+    res->t_h_nextn = cur;
+
+    cur = ggml_get_rows(ctx0, cur, inp_out_ids);
+    cb(cur, "mtp_shared_head_norm", -1);
+
+    cur = build_lora_mm(model.output, cur, model.output_s);
+
+    cb(cur, "result_output", -1);
+    res->t_logits = cur;
+}
+
 template struct llama_model_mellum::graph<false>;
 template struct llama_model_mellum::graph<true>;
+template struct llama_model_mellum::graph_mtp<false>;
+template struct llama_model_mellum::graph_mtp<true>;

src/models/models.h

@@ -466,6 +466,11 @@ struct llama_model_mellum : public llama_model_base {
         graph(const llama_model & model, const llm_graph_params & params);
     };
 
+    template <bool iswa>
+    struct graph_mtp : public llm_graph_context {
+        graph_mtp(const llama_model & model, const llm_graph_params & params);
+    };
+
     std::unique_ptr<llm_graph_context> build_arch_graph(const llm_graph_params & params) const override;
 };