example/ble_throughput:

Fixed the throughput wasting memory and packet loss issues.
Fixed the throughput crash bug because of using the Mutex.

components/bt/bluedroid/api/esp_gatt_common_api.c

@@ -46,4 +46,13 @@ esp_err_t esp_ble_gatt_set_local_mtu (uint16_t mtu)
     arg.set_mtu.mtu = mtu;
 
     return (btc_transfer_context(&msg, &arg, sizeof(btc_ble_gatt_com_args_t), NULL) == BT_STATUS_SUCCESS ? ESP_OK : ESP_FAIL);
-}
+}
+
+#if (BLE_INCLUDED == TRUE)
+extern uint16_t L2CA_GetFreePktBufferNum_LE(void);
+
+uint16_t esp_ble_get_sendable_packets_num ()
+{
+    return L2CA_GetFreePktBufferNum_LE();
+}
+#endif

components/bt/bluedroid/api/include/api/esp_gatt_common_api.h

@@ -44,6 +44,10 @@ extern "C" {
  */
 extern esp_err_t esp_ble_gatt_set_local_mtu (uint16_t mtu);
 
+#if (BLE_INCLUDED == TRUE)
+extern uint16_t esp_ble_get_sendable_packets_num (void);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

components/bt/bluedroid/stack/l2cap/l2c_api.c

@@ -1871,6 +1871,14 @@ BOOLEAN L2CA_CheckIsCongest(UINT16 fixed_cid, UINT16 handle)
 
     return TRUE;
 }
+
+#if (BLE_INCLUDED == TRUE)
+UINT16 L2CA_GetFreePktBufferNum_LE(void)
+{
+    return l2cb.controller_le_xmit_window;
+}
+#endif
+
 /*******************************************************************************
 **
 **  Function        L2CA_RemoveFixedChnl