wip reranking llama.cpp

backend/cpp/llama/grpc-server.cpp

@@ -217,6 +217,7 @@ struct llama_client_slot
 
     bool infill = false;
     bool embedding = false;
+    bool reranker = false;
     bool has_next_token = true;
     bool truncated = false;
     bool stopped_eos = false;
@@ -1409,14 +1410,62 @@ struct llama_server_context
         queue_results.send(res);
     }
 
-    void request_completion(int task_id, json data, bool infill, bool embedding, int multitask_id)
+    void send_rerank(llama_client_slot &slot, const llama_batch & batch)
+    {
+        task_result res;
+        res.id = slot.task_id;
+        res.multitask_id = slot.multitask_id;
+        res.error = false;
+        res.stop = true;
+
+        float score = -1e6f; // Default score if we fail to get embeddings
+
+        if (!params.rerank)
+        {
+            LOG_WARNING("reranking disabled", {
+                                                {"params.rerank", params.rerank},
+                                            });
+        }
+        else
+        {
+            for (int i = 0; i < batch.n_tokens; ++i) {
+                if (!batch.logits[i] || batch.seq_id[i][0] != slot.id) {
+                    continue;
+                }
+
+                const float * embd = llama_get_embeddings_seq(ctx, batch.seq_id[i][0]);
+                if (embd == NULL) {
+                    embd = llama_get_embeddings_ith(ctx, i);
+                }
+
+                if (embd == NULL) {
+                    LOG("failed to get embeddings");
+                    continue;
+                }
+
+                score = embd[0];
+            }
+        }
+
+        // Format result as JSON similar to the embedding function
+        res.result_json = json
+        {
+            {"score", score},
+            {"tokens", slot.n_prompt_tokens}
+        };
+
+        queue_results.send(res);
+    }
+
+    void request_completion(int task_id, json data, bool infill, bool embedding, bool rerank, int multitask_id)
     {
         task_server task;
         task.id = task_id;
         task.target_id = 0;
         task.data = std::move(data);
         task.infill_mode = infill;
         task.embedding_mode = embedding;
+        task.reranking_mode = rerank;
         task.type = TASK_TYPE_COMPLETION;
         task.multitask_id = multitask_id;
 
@@ -1548,7 +1597,7 @@ struct llama_server_context
             subtask_data["prompt"] = subtask_data["prompt"][i];
 
             // subtasks inherit everything else (infill mode, embedding mode, etc.)
-            request_completion(subtask_ids[i], subtask_data, multiprompt_task.infill_mode, multiprompt_task.embedding_mode, multitask_id);
+            request_completion(subtask_ids[i], subtask_data, multiprompt_task.infill_mode, multiprompt_task.embedding_mode, multiprompt_task.reranking_mode, multitask_id);
         }
     }
 
@@ -1587,6 +1636,7 @@ struct llama_server_context
 
                 slot->infill       = task.infill_mode;
                 slot->embedding    = task.embedding_mode;
+                slot->reranker    = task.reranking_mode;
                 slot->task_id      = task.id;
                 slot->multitask_id = task.multitask_id;
 
@@ -2030,6 +2080,14 @@ struct llama_server_context
                     continue;
                 }
 
+                if (slot.reranker)
+                {
+                    send_rerank(slot, batch_view);
+                    slot.release();
+                    slot.i_batch = -1;
+                    continue;
+                }
+
                 completion_token_output result;
                 const llama_token id = common_sampler_sample(slot.ctx_sampling, ctx, slot.i_batch - i);
 

backend/cpp/llama/utils.hpp

@@ -61,6 +61,7 @@ struct task_server {
     json data;
     bool infill_mode = false;
     bool embedding_mode = false;
+    bool reranking_mode = false;
     int multitask_id = -1;
 };