UCP/CORE: Optional warnings about unused config modifications.

Author: rakhmets

src/ucp/core/ucp_context.c

@@ -592,6 +592,11 @@ static ucs_config_field_t ucp_context_config_table[] = {
    "resulting performance.",
    ucs_offsetof(ucp_context_config_t, node_local_id), UCS_CONFIG_TYPE_ULUNITS},
 
+   {UCP_WARN_UNUSED_CONFIG_MODIFICATIONS, "y",
+    "Issue a warning about configuration modifications which were not applied.",
+    ucs_offsetof(ucp_context_config_t, warn_unused_config_modifications),
+    UCS_CONFIG_TYPE_BOOL},
+
   {NULL}
 };
 

src/ucp/core/ucp_context.h

@@ -221,6 +221,8 @@ typedef struct ucp_context_config {
     int                                    proto_use_single_net_device;
     /** Local identificator on a single node */
     unsigned long                          node_local_id;
+    /** Issue a warning in case of unused configuration modifications */
+    int                                    warn_unused_config_modifications;
 } ucp_context_config_t;
 
 
@@ -594,6 +596,9 @@ typedef struct ucp_tl_iface_atomic_flags {
     ucs_assert(ucp_memory_type_detect(_context, _buffer, _length) == (_mem_type))
 
 
+#define UCP_WARN_UNUSED_CONFIG_MODIFICATIONS "WARN_UNUSED_CONFIG_MODIFICATIONS"
+
+
 extern ucp_am_handler_t *ucp_am_handlers[];
 extern const char       *ucp_feature_str[];
 

src/ucp/core/ucp_worker.c

@@ -2294,30 +2294,37 @@ ucs_thread_mode_t ucp_worker_get_thread_mode(uint64_t worker_flags)
     return UCS_THREAD_MODE_SINGLE;
 }
 
-static void ucp_warn_unused_uct_config(ucp_context_h context)
+static void ucp_warn_unused_config_modifications(const ucp_context_h context)
 {
-    unsigned num_unused_cached_kv = 0;
-    ucs_string_buffer_t unused_cached_uct_cfg;
-    ucs_config_cached_key_t *key_val;
+    const ucs_config_cached_key_t *key;
+    ucs_string_buffer_t unused_modifications;
+    unsigned num_unused_modifications;
 
-    ucs_string_buffer_init(&unused_cached_uct_cfg);
+    if (!context->config.ext.warn_unused_config_modifications) {
+        return;
+    }
+
+    ucs_string_buffer_init(&unused_modifications);
+    num_unused_modifications = 0;
 
-    ucs_list_for_each(key_val, &context->cached_key_list, list) {
-        if (!key_val->used) {
-            ucs_string_buffer_appendf(&unused_cached_uct_cfg, "%s=%s,",
-                                      key_val->key, key_val->value);
-            ++num_unused_cached_kv;
+    ucs_list_for_each(key, &context->cached_key_list, list) {
+        if (!key->used) {
+            ucs_string_buffer_appendf(&unused_modifications, "%s=%s,", key->key,
+                                      key->value);
+            ++num_unused_modifications;
         }
     }
 
-    if (num_unused_cached_kv > 0) {
-        ucs_string_buffer_rtrim(&unused_cached_uct_cfg , ",");
-        ucs_warn("invalid configuration%s: %s",
-                 (num_unused_cached_kv > 1) ? "s" : "",
-                 ucs_string_buffer_cstr(&unused_cached_uct_cfg));
+    if (num_unused_modifications > 0) {
+        ucs_string_buffer_rtrim(&unused_modifications , ",");
+        ucs_warn("unused configuration%s: %s\n"
+                 "(set %s%s=n to suppress this warning)",
+                 (num_unused_modifications > 1) ? "s" : "",
+                 ucs_string_buffer_cstr(&unused_modifications),
+                 UCS_DEFAULT_ENV_PREFIX, UCP_WARN_UNUSED_CONFIG_MODIFICATIONS);
     }
 
-    ucs_string_buffer_cleanup(&unused_cached_uct_cfg);
+    ucs_string_buffer_cleanup(&unused_modifications);
 }
 
 static void
@@ -2677,8 +2684,7 @@ ucs_status_t ucp_worker_create(ucp_context_h context,
      */
     ucs_config_parser_print_env_vars_once(context->config.env_prefix);
 
-    /* Warn unused cached uct configuration */
-    ucp_warn_unused_uct_config(context);
+    ucp_warn_unused_config_modifications(context);
 
     ucp_worker_set_max_am_header(worker);
 

test/gtest/ucp/test_ucp_worker.cc

@@ -1008,3 +1008,18 @@ UCS_TEST_P(test_worker_cpu_mask, all_cpus)
 }
 
 UCP_INSTANTIATE_TEST_CASE_TLS(test_worker_cpu_mask, all, "all")
+
+class test_unused_config_modifications : public test_ucp_context {
+public:
+    test_unused_config_modifications()
+    {
+        ucp_config_modify(m_ucp_config, "QWERTY", "QWERTY");
+        ucp_config_modify(m_ucp_config, "WARN_UNUSED_CONFIG_MODIFICATIONS",
+                          "n");
+    }
+};
+
+UCS_TEST_P(test_unused_config_modifications, hidden_warning)
+{}
+
+UCP_INSTANTIATE_TEST_CASE_TLS(test_unused_config_modifications, self, "self")