Merge "Add new cpu_util meter recording CPU utilization %."

ceilometer/compute/libvirt.py

@@ -17,6 +17,8 @@
 # under the License.
 
 import copy
+import datetime
+import multiprocessing
 
 from lxml import etree
 
@@ -154,13 +156,46 @@ class CPUPollster(LibVirtPollster):
 
     LOG = log.getLogger(__name__ + '.cpu')
 
+    utilization_map = {}
+
+    def get_cpu_util(self, instance, cpu_info):
+        prev_times = self.utilization_map.get(instance.uuid)
+        self.utilization_map[instance.uuid] = (cpu_info['cpu_time'],
+                                               datetime.datetime.now())
+        cpu_util = 0.0
+        if prev_times:
+            prev_cpu = prev_times[0]
+            prev_timestamp = prev_times[1]
+            delta = self.utilization_map[instance.uuid][1] - prev_timestamp
+            elapsed = (delta.seconds * (10 ** 6) + delta.microseconds) * 1000
+            cores_fraction = instance.vcpus * 1.0 / multiprocessing.cpu_count()
+            # account for cpu_time being reset when the instance is restarted
+            time_used = (cpu_info['cpu_time'] - prev_cpu
+                         if prev_cpu <= cpu_info['cpu_time'] else
+                         cpu_info['cpu_time'])
+            cpu_util = 100 * cores_fraction * time_used / elapsed
+        return cpu_util
+
     def get_counters(self, manager, instance):
         conn = get_libvirt_connection()
         self.LOG.info('checking instance %s', instance.uuid)
         try:
             cpu_info = conn.get_info(instance)
             self.LOG.info("CPUTIME USAGE: %s %d",
-                          instance, cpu_info['cpu_time'])
+                          dict(instance), cpu_info['cpu_time'])
+            cpu_util = self.get_cpu_util(instance, cpu_info)
+            self.LOG.info("CPU UTILIZATION %%: %s %0.2f",
+                          dict(instance), cpu_util)
+            # FIXME(eglynn): once we have a way of configuring which measures
+            #                are published to each sink, we should by default
+            #                disable publishing this derived measure to the
+            #                metering store, only publishing to those sinks
+            #                that specifically need it
+            yield make_counter_from_instance(instance,
+                                             name='cpu_util',
+                                             type=counter.TYPE_GAUGE,
+                                             volume=cpu_util,
+                                             )
             yield make_counter_from_instance(instance,
                                              name='cpu',
                                              type=counter.TYPE_CUMULATIVE,

tests/compute/test_libvirt.py

@@ -27,6 +27,7 @@ else:
     libvirt_missing = False
 
 import mock
+import time
 
 from nova import flags
 
@@ -39,11 +40,12 @@ import mox
 import re
 
 
-def fake_libvirt_conn(moxobj):
+def fake_libvirt_conn(moxobj, count=1):
     conn = moxobj.CreateMockAnything()
     conn._conn = moxobj.CreateMockAnything()
     moxobj.StubOutWithMock(libvirt, 'get_libvirt_connection')
-    libvirt.get_libvirt_connection().AndReturn(conn)
+    for _ in xrange(count):
+        libvirt.get_libvirt_connection().AndReturn(conn)
     return conn
 
 
@@ -210,13 +212,27 @@ class TestCPUPollster(TestLibvirtBase):
         self.pollster = libvirt.CPUPollster()
 
     def test_get_counter(self):
-        expected_cpu_time = 12345
-
-        conn = fake_libvirt_conn(self.mox)
+        self.instance.vcpus = 1
+        conn = fake_libvirt_conn(self.mox, 3)
         self.mox.StubOutWithMock(conn, 'get_info')
-        conn.get_info(self.instance).AndReturn({'cpu_time': expected_cpu_time})
+        conn.get_info(self.instance).AndReturn({'cpu_time': 1 * (10 ** 6)})
+        conn.get_info(self.instance).AndReturn({'cpu_time': 3 * (10 ** 6)})
+        # cpu_time resets on instance restart
+        conn.get_info(self.instance).AndReturn({'cpu_time': 2 * (10 ** 6)})
         self.mox.ReplayAll()
-        counters = list(self.pollster.get_counters(self.manager,
-                                                   self.instance))
-        self.assertEquals(len(counters), 1)
-        assert counters[0].volume == expected_cpu_time
+
+        def _verify_cpu_metering(zero, expected_time):
+            counters = list(self.pollster.get_counters(self.manager,
+                                                       self.instance))
+            self.assertEquals(len(counters), 2)
+            assert counters[0].name == 'cpu_util'
+            assert (counters[0].volume == 0.0 if zero else
+                    counters[0].volume > 0.0)
+            assert counters[1].name == 'cpu'
+            assert counters[1].volume == expected_time
+            # ensure elapsed time between polling cycles is non-zero
+            time.sleep(0.001)
+
+        _verify_cpu_metering(True, 1 * (10 ** 6))
+        _verify_cpu_metering(False, 3 * (10 ** 6))
+        _verify_cpu_metering(False, 2 * (10 ** 6))