llama: fix llama-model-saver (#20503)

* llama : add fd-based model loading via llama_model_load_from_fd

* llama : address review feedback for fd-based model loading

* llama : use FILE pointer instead of fd in public API

* llama : use FILE pointer consistently, address review feedback

* fixup

* fix tensor names

* fix llama-model-saver

* roundtrip tests

* fixup

* refactor tests

* fix prints

* fix model saving

* fix CI, disable Chameleon

* print seed

---------

Co-authored-by: Siddhesh2377 <siddheshsonar2377@gmail.com>

src/llama-model.cpp

@@ -1624,7 +1624,7 @@ void llama_model::load_hparams(llama_model_loader & ml) {
 
                 // (optional) temperature tuning - used by mistral-large
                 ml.get_key(LLM_KV_ATTENTION_TEMPERATURE_SCALE,  hparams.f_attn_temp_scale,       false);
-                ml.get_key(LLM_KV_ATTENTION_TEMPERATURE_LENGTH, hparams.n_attn_temp_floor_scale, false);
+                ml.get_key(LLM_KV_ATTENTION_TEMPERATURE_LENGTH, hparams.n_attn_temp_floor_scale, false); // FIXME why not use temperature_length?
 
                 hparams.f_attn_temp_offset = 0.0f;
 
@@ -7607,14 +7607,15 @@ bool llama_model::load_tensors(llama_model_loader & ml) {
                 buf_map.emplace(idx, buf);
             }
         }
-        pimpl->ctxs_bufs.emplace_back(std::move(ctx_ptr), std::move(bufs));
 
-        for (auto & buf : buf_map) {
+        for (auto & buf : bufs) {
             // indicate that this buffer contains weights
             // this is used by ggml_backend_sched to improve op scheduling: ops that use a weight are preferably scheduled to the backend that contains the weight
-            ggml_backend_buffer_set_usage(buf.second, GGML_BACKEND_BUFFER_USAGE_WEIGHTS);
+            ggml_backend_buffer_set_usage(buf.get(), GGML_BACKEND_BUFFER_USAGE_WEIGHTS);
         }
 
+        pimpl->ctxs_bufs.emplace_back(std::move(ctx_ptr), std::move(bufs));
+
         ctx_buf_maps.emplace_back(ctx, buf_map);
     }