diff --git a/wally/sensors.py b/wally/sensors.py
index 60830a1..89bc224 100644
--- a/wally/sensors.py
+++ b/wally/sensors.py
@@ -1,7 +1,7 @@
 import bz2
 import array
 import logging
-from typing import List, Dict, Tuple
+from typing import Dict
 
 import numpy
 
@@ -21,37 +21,6 @@
 logger = logging.getLogger("wally")
 
 
-sensor_units = {
-    "system-cpu.idle": "",
-    "system-cpu.nice": "",
-    "system-cpu.user": "",
-    "system-cpu.sys": "",
-    "system-cpu.iowait": "",
-    "system-cpu.irq": "",
-    "system-cpu.sirq": "",
-    "system-cpu.steal": "",
-    "system-cpu.guest": "",
-
-    "system-cpu.procs_blocked": "",
-    "system-cpu.procs_queue_x10": "",
-
-    "net-io.recv_bytes": "B",
-    "net-io.recv_packets": "",
-    "net-io.send_bytes": "B",
-    "net-io.send_packets": "",
-
-    "block-io.io_queue": "",
-    "block-io.io_time": "ms",
-    "block-io.reads_completed": "",
-    "block-io.rtime": "ms",
-    "block-io.sectors_read": "B",
-    "block-io.sectors_written": "B",
-    "block-io.writes_completed": "",
-    "block-io.wtime": "ms",
-    "block-io.weighted_io_time": "ms"
-}
-
-
 # TODO(koder): in case if node has more than one role sensor settings might be incorrect
 class StartSensorsStage(Stage):
     priority = StepOrder.START_SENSORS
@@ -118,27 +87,29 @@
 
 def collect_sensors_data(ctx: TestRun, stop: bool = False):
     rstorage = ResultStorage(ctx.storage)
+    total_sz = 0
+
+    logger.info("Start loading sensors")
     for node in ctx.nodes:
         node_id = node.node_id
         if node_id in ctx.sensors_run_on:
+            func = node.conn.sensors.stop if stop else node.conn.sensors.get_updates
 
-            if stop:
-                func = node.conn.sensors.stop
-            else:
-                func = node.conn.sensors.get_updates
+            # hack to calculate total transferred size
+            offset_map, compressed_blob, compressed_collected_at_b = func()
+            data_tpl = (offset_map, compressed_blob, compressed_collected_at_b)
 
-            # TODO: units should came along with data
-            # TODO: process raw sensors data
+            total_sz += len(compressed_blob) + len(compressed_collected_at_b) + sum(map(len, offset_map)) + \
+                16 * len(offset_map)
 
-            for path, value, is_array in sensors_rpc_plugin.unpack_rpc_updates(func()):
+            for path, value, is_array, units in sensors_rpc_plugin.unpack_rpc_updates(data_tpl):
                 if path == 'collected_at':
                     ds = DataSource(node_id=node_id, metric='collected_at', tag='csv')
-                    rstorage.append_sensor(numpy.array(value), ds, 'us')
+                    rstorage.append_sensor(numpy.array(value), ds, units)
                 else:
                     sensor, dev, metric = path.split(".")
                     ds = DataSource(node_id=node_id, metric=metric, dev=dev, sensor=sensor, tag='csv')
                     if is_array:
-                        units = sensor_units["{}.{}".format(sensor, metric)]
                         rstorage.append_sensor(numpy.array(value), ds, units)
                     else:
                         if metric == 'historic':
@@ -146,6 +117,7 @@
                         else:
                             assert metric in ('perf_dump', 'historic_js')
                             rstorage.put_sensor_raw(value, ds(tag='js'))
+    logger.info("Download %sB of sensors data", utils.b2ssize(total_sz))
 
 
 
@@ -156,33 +128,3 @@
     def run(self, ctx: TestRun) -> None:
         collect_sensors_data(ctx, True)
 
-
-# def delta(func, only_upd=True):
-#     prev = {}
-#     while True:
-#         for dev_name, vals in func():
-#             if dev_name not in prev:
-#                 prev[dev_name] = {}
-#                 for name, (val, _) in vals.items():
-#                     prev[dev_name][name] = val
-#             else:
-#                 dev_prev = prev[dev_name]
-#                 res = {}
-#                 for stat_name, (val, accum_val) in vals.items():
-#                     if accum_val:
-#                         if stat_name in dev_prev:
-#                             delta = int(val) - int(dev_prev[stat_name])
-#                             if not only_upd or 0 != delta:
-#                                 res[stat_name] = str(delta)
-#                         dev_prev[stat_name] = val
-#                     elif not only_upd or '0' != val:
-#                         res[stat_name] = val
-#
-#                 if only_upd and len(res) == 0:
-#                     continue
-#                 yield dev_name, res
-#         yield None, None
-#
-#
-
-