增加 load_balance 配置项：TFE 支持 round_robin/least_conn 负载均衡算法

platform/include/internal/proxy.h

@@ -80,6 +80,12 @@ struct tfe_proxy_accept_para
 	unsigned int keyring_id;
 };
 
+enum tfe_load_balance_algo
+{
+	LEAST_CONN = 0,
+	ROUND_ROBIN = 1,
+};
+
 struct tfe_proxy
 {
 	char name[TFE_SYMBOL_MAX];
@@ -128,6 +134,9 @@ struct tfe_proxy
 	/* cpu affinity */
 	unsigned int enable_cpu_affinity;
 	unsigned int cpu_affinity_mask[TFE_THREAD_MAX];
+
+	/* load balancing */
+	enum tfe_load_balance_algo load_balance;
 };
 
 extern struct tfe_proxy * g_default_proxy;