server: fix report progress for loading spec models, add "stages" list (#24870)

* server: fix report progress for loading spec models, add "stages" list

* improve

* nits

* nits 2

tools/server/README.md

@@ -1863,11 +1863,15 @@ Example events:
   "data": {
     "status": "loading",
     "progress": {
-      "stage": "fit_params",
+      "stages": ["text_model", "spec_model", "mmproj_model"],
-      "value": 0.5 // from 0.0 to 1.0 ; note: not all stages have this "value"
+      "current": "text_model",
+      "value": 0.5
     }
   }
 }
+// note for "loading" status:
+// - subsequent events will follow the same order of "stages" list
+// - mmap is may report incorrect progress on some platforms; if you need exact progress, use --no-mmap
 
 {
   "model": "...",

tools/server/server-context.cpp

@@ -962,6 +962,7 @@ private:
     struct load_progress_data {
         server_context_impl * ctx;
         std::string stage;
+        std::vector<std::string> stages;
         int64_t t_last_load_progress_ms = 0;
         load_progress_data(server_context_impl * ctx, const std::string & stage) : ctx(ctx), stage(stage) {}
     };
@@ -982,7 +983,8 @@ private:
         }
         if (d->ctx->callback_state) {
             d->ctx->callback_state(SERVER_STATE_LOADING, {
-                {"stage", d->stage},
+                {"stages", d->stages},
+                {"current", d->stage},
                 {"value", progress},
             });
         }
@@ -994,16 +996,40 @@ private:
     bool load_model(common_params & params) {
         load_progress_data load_progress_text  (this, "text_model");
         load_progress_data load_progress_mmproj(this, "mmproj_model");
+        load_progress_data load_progress_spec  (this, "spec_model");
 
-        bool is_resume = sleeping;
+        const bool is_resume = sleeping;
-
-        SRV_INF("loading model '%s'\n", params.model.path.c_str());
 
         params_base = params;
         params_base.n_outputs_max = server_n_outputs_max(params_base);
 
+        const bool has_mmproj = !params.mmproj.path.empty();
+        const bool has_draft = params.speculative.has_dft();
+        const bool spec_mtp = std::find(params_base.speculative.types.begin(),
+                                        params_base.speculative.types.end(),
+                                        COMMON_SPECULATIVE_TYPE_DRAFT_MTP) != params_base.speculative.types.end();
+        const bool has_spec = has_draft || spec_mtp;
+
+        if (callback_state) {
+            std::vector<std::string> stages = {"text_model"};
+            if (has_spec) {
+                stages.push_back("spec_model");
+            }
+            if (has_mmproj) {
+                stages.push_back("mmproj_model");
+            }
+            load_progress_text.stages   = stages;
+            load_progress_mmproj.stages = stages;
+            load_progress_spec.stages   = stages;
+
+            // trigger 0% progress
+            load_progress_callback(0.0f, &load_progress_text);
+        }
+
+
+        SRV_INF("loading model '%s'\n", params.model.path.c_str());
+
         std::string & mmproj_path = params_base.mmproj.path;
-        bool has_mmproj = !mmproj_path.empty();
         mtmd_context_params mparams = mtmd_context_params_default();
         if (has_mmproj) {
             mparams.use_gpu          = params_base.mmproj_use_gpu;
@@ -1050,16 +1076,7 @@ private:
 
         // optionally reserve VRAM for the draft / MTP context before fitting the target model
         if (params_base.fit_params) {
-            if (callback_state) {
+            if (has_spec) {
-                callback_state(SERVER_STATE_LOADING, {{"stage", "fit_params"}});
-            }
-
-            const bool spec_mtp = std::find(params_base.speculative.types.begin(),
-                                            params_base.speculative.types.end(),
-                                            COMMON_SPECULATIVE_TYPE_DRAFT_MTP) != params_base.speculative.types.end();
-            const bool has_draft = params_base.speculative.has_dft();
-
-            if (has_draft || spec_mtp) {
                 common_params params_dft = params_base;
                 bool measure_model_bytes = true;
 
@@ -1151,11 +1168,7 @@ private:
 
         add_bos_token = llama_vocab_get_add_bos(vocab);
 
-        if (params_base.speculative.has_dft()) {
+        if (has_draft) {
-            if (callback_state) {
-                callback_state(SERVER_STATE_LOADING, {{"stage", "spec_model"}});
-            }
-
             // TODO speculative: move to common/speculative.cpp?
             const auto & params_spec = params_base.speculative.draft;
 
@@ -1178,6 +1191,10 @@ private:
 
             auto mparams_dft = common_model_params_to_llama(params_dft);
 
+            // progress callback
+            mparams_dft.progress_callback           = load_progress_callback;
+            mparams_dft.progress_callback_user_data = &load_progress_spec;
+
             model_dft.reset(llama_model_load_from_file(params_dft.model.path.c_str(), mparams_dft));
             if (model_dft == nullptr) {
                 SRV_ERR("failed to load draft model, '%s'\n", params_dft.model.path.c_str());
@@ -1186,10 +1203,6 @@ private:
 
             auto cparams = common_context_params_to_llama(params_dft);
 
-            const bool spec_mtp = std::find(params_base.speculative.types.begin(),
-                                            params_base.speculative.types.end(),
-                                            COMMON_SPECULATIVE_TYPE_DRAFT_MTP) != params_base.speculative.types.end();
-
             if (spec_mtp) {
                 cparams.ctx_type = LLAMA_CONTEXT_TYPE_MTP;
             }
@@ -1203,8 +1216,10 @@ private:
 
             params_base.speculative.draft.ctx_tgt = ctx_tgt;
             params_base.speculative.draft.ctx_dft = ctx_dft.get();
-        } else if (std::find(params_base.speculative.types.begin(), params_base.speculative.types.end(),
+        } else if (spec_mtp) {
-                             COMMON_SPECULATIVE_TYPE_DRAFT_MTP) != params_base.speculative.types.end()) {
+            // no new model load, so we simply report 0.0 and 1.0 progress
+            load_progress_callback(0.0f, &load_progress_spec);
+
             SRV_INF("creating MTP draft context against the target model '%s'\n",
                     params_base.model.path.c_str());
 
@@ -1224,6 +1239,8 @@ private:
 
             params_base.speculative.draft.ctx_tgt = ctx_tgt;
             params_base.speculative.draft.ctx_dft = ctx_dft.get();
+
+            load_progress_callback(1.0f, &load_progress_spec);
         }
 
         if (has_mmproj) {