Normalize CPU stats (#2154)

* Normalize CPU stats

* Change fixture to make it clearer

* guard for 0

* Update supervisor/docker/stats.py

Co-authored-by: Pascal Vizeli <pvizeli@syshack.ch>

* Update stats.py

* Update stats.py

Co-authored-by: Pascal Vizeli <pvizeli@syshack.ch>

supervisor/docker/stats.py

@@ -45,12 +45,11 @@ class DockerStats:
             stats["cpu_stats"]["system_cpu_usage"]
             - stats["precpu_stats"]["system_cpu_usage"]
         )
-        online_cpu = stats["cpu_stats"]["online_cpus"]
 
-        if online_cpu == 0.0:
-            online_cpu = len(stats["cpu_stats"]["cpu_usage"]["percpu_usage"])
         if system_delta > 0.0 and cpu_delta > 0.0:
-            self._cpu = (cpu_delta / system_delta) * online_cpu * 100.0
+            self._cpu = (cpu_delta / system_delta) * 100.0
+        else:
+            self._cpu = 0.0
 
     def _calc_network(self, networks):
         """Calculate Network IO stats."""

tests/docker/test_stats.py

@@ -0,0 +1,20 @@
+"""Test docker stats."""
+from supervisor.docker.stats import DockerStats
+
+from tests.common import load_json_fixture
+
+
+def test_cpu_presentage(docker):
+    """Test CPU presentage."""
+    stats_fixtrue = load_json_fixture("container_stats.json")
+    stats = DockerStats(stats_fixtrue)
+
+    stats._calc_cpu_percent(stats_fixtrue)  # pylint: disable=protected-access
+    assert stats.cpu_percent == 90.0
+
+    stats_fixtrue["cpu_stats"]["cpu_usage"]["total_usage"] = 0
+    stats_fixtrue["precpu_stats"]["cpu_usage"]["total_usage"] = 0
+    stats_fixtrue["cpu_stats"]["system_cpu_usage"] = 0
+    stats_fixtrue["precpu_stats"]["system_cpu_usage"] = 0
+    stats._calc_cpu_percent(stats_fixtrue)  # pylint: disable=protected-access
+    assert stats.cpu_percent == 0.0

tests/fixtures/container_stats.json

@@ -0,0 +1,20 @@
+{
+  "cpu_stats": {
+    "cpu_usage": {
+      "total_usage": 190
+    },
+    "system_cpu_usage": 200,
+    "online_cpus": 24
+  },
+  "precpu_stats": {
+    "cpu_usage": {
+      "total_usage": 100
+    },
+    "system_cpu_usage": 100,
+    "online_cpus": 24
+  },
+  "memory_stats": {
+    "usage": 250000000,
+    "limit": 330000000000
+  }
+}