monotonic timestamps: document they are milliseconds

lib/cache.h

@@ -78,7 +78,7 @@ struct kr_cache
 
 	uint32_t ttl_min, ttl_max; /**< Maximum TTL of inserted entries */
 	struct timeval last_clear_walltime; /**< Time of last cache clear */
-	uint64_t last_clear_monotime;  /**< Last cache clear in monotonic time */
+	uint64_t last_clear_monotime;  /**< Last cache clear in monotonic milliseconds */
 };
 
 /**

lib/rplan.h

@@ -84,11 +84,11 @@ struct kr_query {
 	uint32_t secret;
 	uint16_t fails;
 	uint16_t reorder; /**< Seed to reorder (cached) RRs in answer or zero. */
-	uint64_t creation_time_mono; /* The time of query's creation.
+	uint64_t creation_time_mono; /* The time of query's creation (milliseconds).
 				 * Or time of creation of an oldest
 				 * ancestor if it is a subquery. */
-	uint64_t timestamp_mono; /**< Time of query created or time of 
-	                          query to upstream resolver */
+	uint64_t timestamp_mono; /**< Time of query created or time of
+	                           * query to upstream resolver (milliseconds). */
 	struct timeval timestamp;
 	struct kr_zonecut zone_cut;
 	struct kr_nsrep ns;

lib/utils.h

@@ -300,6 +300,10 @@ static inline const char *lua_push_printf(lua_State *L, const char *fmt, ...)
 	return ret;
 }
 
+/** The current time in monotonic milliseconds.
+ *
+ * \note it may be outdated in case of long callbacks; see uv_now().
+ */
 KR_EXPORT
 uint64_t kr_now();