Add CPU frequency to host stats

This change set builds on the prior function and includes a function to
gather the CPU frequency from the system.  This change completes the
functions needed to get the proper CPU Host Stats from within Nova for
the PowerVM hypervisor.

Change-Id: I7a2e9d76d22d3d857b14a9f378e24d6d73423ecc

nova_powervm/tests/virt/powervm/test_host.py

@@ -107,10 +107,13 @@ class TestHostCPUStats(test.TestCase):
                 return lpar
         return None
 
+    @mock.patch('nova_powervm.virt.powervm.host.HostCPUStats._get_cpu_freq')
     @mock.patch('pypowervm.tasks.monitor.util.MetricCache._refresh_if_needed')
     @mock.patch('pypowervm.tasks.monitor.util.ensure_ltm_monitors')
-    def test_update_internal_metric(self, mock_ensure_ltm, mock_refresh):
+    def test_update_internal_metric(self, mock_ensure_ltm, mock_refresh,
+                                    mock_cpu_freq):
         host_stats = pvm_host.HostCPUStats(self.adpt, 'host_uuid')
+        mock_cpu_freq.return_value = 4116.0
 
         # Make sure None is returned if there is no data.
         host_stats.cur_phyp = None
@@ -124,7 +127,8 @@ class TestHostCPUStats(test.TestCase):
 
         # Validate the dictionary...
         expect = {'iowait': 0, 'idle': 1.6125096675799704e+16,
-                  'kernel': 58599310268, 'user': 789903553028}
+                  'kernel': 58599310268, 'user': 789903553028,
+                  'frequency': 4116.0}
         self.assertEqual(expect, host_stats.cur_data)
 
         # Now 'increment' it with a new current/previous
@@ -135,9 +139,18 @@ class TestHostCPUStats(test.TestCase):
         # Validate this dictionary.  Note that the values are still higher
         # overall, even though we add the 'deltas' from each VM.
         expect = {'iowait': 0, 'idle': 1.6125066665694504e+16,
-                  'kernel': 58599310268, 'user': 819913658228}
+                  'kernel': 58599310268, 'user': 819913658228,
+                  'frequency': 4116.0}
         self.assertEqual(expect, host_stats.cur_data)
 
+    @mock.patch('subprocess.check_output')
+    @mock.patch('pypowervm.tasks.monitor.util.MetricCache._refresh_if_needed')
+    @mock.patch('pypowervm.tasks.monitor.util.ensure_ltm_monitors')
+    def test_get_cpu_freq(self, mock_ensure_ltm, mock_refresh, mock_cmd):
+        host_stats = pvm_host.HostCPUStats(self.adpt, 'host_uuid')
+        mock_cmd.return_value = '4116.000000MHz\n'
+        self.assertEqual(4116.0, host_stats._get_cpu_freq())
+
     @mock.patch('pypowervm.tasks.monitor.util.MetricCache._refresh_if_needed')
     @mock.patch('pypowervm.tasks.monitor.util.ensure_ltm_monitors')
     def test_gather_user_cycles(self, mock_ensure_ltm, mock_refresh):

nova_powervm/virt/powervm/driver.py

@@ -172,12 +172,7 @@ class PowerVMDriver(driver.ComputeDriver):
 
     def get_host_cpu_stats(self):
         """Return the current CPU state of the host."""
-        host_stats = self.host_cpu_stats.get_host_cpu_stats()
+        return self.host_cpu_stats.get_host_cpu_stats()
-
-        # TODO(thorst) Implement a frequency check.
-        host_stats['frequency'] = 3500
-
-        return host_stats
 
     def spawn(self, context, instance, image_meta, injected_files,
               admin_password, network_info=None, block_device_info=None,

nova_powervm/virt/powervm/host.py

@@ -18,6 +18,7 @@ import math
 from nova.compute import arch
 from nova.compute import hv_type
 from nova.compute import vm_mode
+import subprocess
 
 from oslo_concurrency import lockutils
 from oslo_log import log as logging
@@ -159,9 +160,12 @@ class HostCPUStats(pcm_util.MetricCache):
         # Idle is the subtraction of all.
         idle_cycles = tot_cycles - user_cycles - fw_cycles
 
+        # Get the processor frequency.
+        freq = self._get_cpu_freq()
+
         # Now save these cycles to the internal data structure.
         self.cur_data = {'idle': idle_cycles, 'kernel': fw_cycles,
-                         'user': user_cycles, 'iowait': 0}
+                         'user': user_cycles, 'iowait': 0, 'frequency': freq}
 
     def _gather_user_cycles(self):
         """The estimated total user cycles.
@@ -205,6 +209,12 @@ class HostCPUStats(pcm_util.MetricCache):
                             else self.prev_data['user'])
         return prev_user_cycles + vm_delta_cycles + vios_delta_cycles
 
+    @staticmethod
+    def _get_cpu_freq():
+        # The output will be similar to '4116.000000MHz' on a POWER system.
+        cmd = ['/usr/bin/awk', '/clock/ {print $3; exit}', '/proc/cpuinfo']
+        return float(subprocess.check_output(cmd).rstrip("MHz\n"))
+
     def _delta_proc_cycles(self, samples, prev_samples):
         """Sums all the processor delta cycles for a set of VM/VIOS samples.