server : coherent log output for KV cache full (ggml-org#6637)

Author: phymbert

examples/server/server.cpp

@@ -1083,7 +1083,7 @@ struct server_context {
                 };
 
                 if (llama_decode(ctx, batch_view) != 0) {
-                    LOG_TEE("%s: llama_decode() failed\n", __func__);
+                    LOG_ERROR("llama_decode() failed", {});
                     return;
                 }
             }
@@ -1281,7 +1281,11 @@ struct server_context {
     }
 
     void send_error(const int id_task, const int id_multi, const std::string & error, const enum error_type type = ERROR_TYPE_SERVER) {
-        LOG_TEE("task %i - error: %s\n", id_task, error.c_str());
+        LOG_ERROR("task error", {
+            {"id_multi", id_multi},
+            {"id_task", id_task},
+            {"error", error},
+        });
 
         server_task_result res;
         res.id       = id_task;
@@ -2186,7 +2190,11 @@ struct server_context {
             if (ret != 0) {
                 if (n_batch == 1 || ret < 0) {
                     // if you get here, it means the KV cache is full - try increasing it via the context size
-                    LOG_TEE("%s : failed to decode the batch, n_batch = %d, ret = %d\n", __func__, n_batch, ret);
+                    LOG_ERROR("failed to decode the batch: KV cache is full - try increasing it via the context size", {
+                        {"i",   i},
+                        {"n_batch",  ret},
+                        {"ret",   ret},
+                    });
                     for (auto & slot : slots) {
                         slot.state = SLOT_STATE_PROCESSING;
                         slot.command = SLOT_COMMAND_NONE;
@@ -2196,12 +2204,16 @@ struct server_context {
                     break; // break loop of n_batch
                 }
 
-                LOG_TEE("%s : failed to find free space in the KV cache, retrying with smaller n_batch = %d\n", __func__, n_batch / 2);
-
                 // retry with half the batch size to try to find a free slot in the KV cache
                 n_batch /= 2;
                 i -= n_batch;
 
+                LOG_WARNING("failed to find free space in the KV cache, retrying with smaller batch size - try increasing it via the context size or enable defragmentation", {
+                    {"i",   i},
+                    {"n_batch",  n_batch},
+                    {"ret",   ret},
+                });
+
                 continue; // continue loop of n_batch
             }