model: add NextN/MTP speculative decoding support for GLM_DSA (GLM-5.2)

conversion/glm.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 
-from typing import Iterable, TYPE_CHECKING
+import re
+
+from typing import Callable, Iterable, TYPE_CHECKING
 
 import torch
 
@@ -213,12 +215,47 @@ def set_vocab(self):
 class GlmMoeDsaModel(DeepseekV2Model):
     model_arch = gguf.MODEL_ARCH.GLM_DSA
     skip_mtp = False
+    supports_mtp_export = True
+
+    # Trunk layer count, stashed before indexing so the classmethod
+    # filter_tensors can identify the appended NextN/MTP block (mirrors
+    # HYV3Model / Step35Model).
+    _n_main_layers: int | None = None
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self.block_count = self.hparams["num_hidden_layers"] + self.hparams.get("num_nextn_predict_layers", 0)
+        self.block_count = self.hparams["num_hidden_layers"]
+        if not self.no_mtp:
+            self.block_count += self.hparams.get("num_nextn_predict_layers", 0)
         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
+
+        # GLM-5.2 appends the NextN/MTP block past num_hidden_layers
+        # (model.layers.78 -> blk.78 in the 79-block file).
+        assert cls._n_main_layers is not None
+        is_mtp = (m := re.match(r"model\.layers\.(\d+)\.", name)) is not None and int(m.group(1)) >= cls._n_main_layers
+
+        # --no-mtp: drop the appended NextN block entirely.
+        if is_mtp and cls.no_mtp:
+            return None
+        # --mtp: keep ONLY NextN-block tensors plus the shared embeddings/
+        # norm/lm_head (so the resulting GGUF carries just the draft head).
+        if cls.mtp_only and not is_mtp and name not in (
+            "model.embed_tokens.weight", "model.norm.weight", "lm_head.weight",
+        ):
+            return None
+
+        return name, gen
+
     def set_vocab(self):
         return self._set_vocab_glm()
 
@@ -230,7 +267,7 @@ def set_gguf_parameters(self):
         self.gguf_writer.add_rope_dimension_count(int(rope_dim * partial_rotary_factor))
 
         # NextN/MTP prediction layers
-        if (num_nextn_predict_layers := self.hparams.get("num_nextn_predict_layers")) is not None:
+        if not self.no_mtp and (num_nextn_predict_layers := self.hparams.get("num_nextn_predict_layers")) is not None:
             self.gguf_writer.add_nextn_predict_layers(num_nextn_predict_layers)
 
         # DSA indexer parameters

src/llama-model.cpp

@@ -2066,7 +2066,6 @@ llama_memory_i * llama_model::create_memory(const llama_memory_params & params,
                 res = nullptr;
             } break;
         case LLM_ARCH_DEEPSEEK32:
-        case LLM_ARCH_GLM_DSA:
             {
                 res = new llama_kv_cache_dsa(
                         *this,
@@ -2083,6 +2082,56 @@ llama_memory_i * llama_model::create_memory(const llama_memory_params & params,
                         nullptr,
                         nullptr);
             } break;
+        case LLM_ARCH_GLM_DSA:
+            {
+                if (params.ctx_type == LLAMA_CONTEXT_TYPE_MTP && hparams.n_layer_nextn > 0) {
+                    // The NextN/MTP draft head runs dense MLA (no DSA indexer), so the
+                    // MTP context uses a plain attention KV cache holding only the
+                    // nextn layer(s) - same pattern as the hybrid Qwen3.5 MTP context.
+                    llama_kv_cache::layer_filter_cb filter =
+                        [&](uint32_t il) { return il >= hparams.n_layer(); };
+
+                    res = new llama_kv_cache(
+                            *this,
+                            hparams,
+                            params.type_k,
+                            params.type_v,
+                            !cparams.flash_attn,
+                            cparams.offload_kqv,
+                            cparams.kv_unified,
+                            cparams.n_ctx_seq,
+                            cparams.n_seq_max,
+                            1,
+                            hparams.n_swa,
+                            hparams.swa_type,
+                            nullptr,
+                            filter,
+                            nullptr,
+                            nullptr);
+                } else {
+                    // Main context: DSA cache for the trunk layers only - the nextn
+                    // layer(s) are never attended by the trunk graph.
+                    llama_kv_cache::layer_filter_cb filter = nullptr;
+                    if (hparams.n_layer_nextn > 0) {
+                        filter = [&](uint32_t il) { return il < hparams.n_layer(); };
+                    }
+
+                    res = new llama_kv_cache_dsa(
+                            *this,
+                            params.type_k,
+                            params.type_v,
+                            !cparams.flash_attn,
+                            cparams.offload_kqv,
+                            cparams.kv_unified,
+                            cparams.n_ctx_seq,
+                            cparams.n_seq_max,
+                            1,
+                            hparams.n_swa,
+                            hparams.swa_type,
+                            filter,
+                            nullptr);
+                }
+            } break;
         // Models that need standard caching should rely on recurrent/hybrid
         // checks
         default:
@@ -2188,7 +2237,7 @@ llama_memory_i * llama_model::create_memory(const llama_memory_params & params,
                         filter = [&](uint32_t il) { return il >= hparams.n_layer(); };
                     }
 
-                    if ((arch == LLM_ARCH_STEP35 || arch == LLM_ARCH_HY_V3) && hparams.n_layer_nextn > 0) {
+                    if ((arch == LLM_ARCH_STEP35 || arch == LLM_ARCH_HY_V3 || arch == LLM_ARCH_GLM_DSA) && hparams.n_layer_nextn > 0) {
                         if (params.ctx_type == LLAMA_CONTEXT_TYPE_MTP) {
                             filter = [&](uint32_t il) { return il >= hparams.n_layer(); };
                         } else {