instrument: Add power monitoring support on Gem5 platforms

devlib/__init__.py

@@ -17,6 +17,7 @@ from devlib.instrument.frames import GfxInfoFramesInstrument
 from devlib.instrument.hwmon import HwmonInstrument
 from devlib.instrument.monsoon import MonsoonInstrument
 from devlib.instrument.netstats import NetstatsInstrument
+from devlib.instrument.gem5power import Gem5PowerInstrument
 
 from devlib.trace.ftrace import FtraceCollector
 

devlib/instrument/gem5power.py

@@ -0,0 +1,74 @@
+#    Copyright 2017 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import division
+import csv
+import re
+
+from devlib.platform.gem5 import Gem5SimulationPlatform
+from devlib.instrument import Instrument, CONTINUOUS, MeasurementsCsv
+from devlib.exception import TargetError, HostError
+
+
+class Gem5PowerInstrument(Instrument):
+    '''
+    Instrument enabling power monitoring in gem5
+    '''
+
+    mode = CONTINUOUS
+    roi_label = 'power_instrument'
+    
+    def __init__(self, target, power_sites):
+        '''
+        Parameter power_sites is a list of gem5 identifiers for power values. 
+        One example of such a field:
+            system.cluster0.cores0.power_model.static_power
+        '''
+        if not isinstance(target.platform, Gem5SimulationPlatform):
+            raise TargetError('Gem5PowerInstrument requires a gem5 platform')
+        if not target.has('gem5stats'):
+            raise TargetError('Gem5StatsModule is not loaded')
+        super(Gem5PowerInstrument, self).__init__(target)
+
+        # power_sites is assumed to be a list later
+        if isinstance(power_sites, list):
+            self.power_sites = power_sites
+        else:
+            self.power_sites = [power_sites]
+        self.add_channel('sim_seconds', 'time')
+        for field in self.power_sites:
+            self.add_channel(field, 'power')
+        self.target.gem5stats.book_roi(self.roi_label)
+        self.sample_period_ns = 10000000
+        self.target.gem5stats.start_periodic_dump(0, self.sample_period_ns)
+
+    def start(self):
+        self.target.gem5stats.roi_start(self.roi_label)
+
+    def stop(self):
+        self.target.gem5stats.roi_end(self.roi_label)
+       
+    def get_data(self, outfile):
+        active_sites = [c.site for c in self.active_channels]
+        with open(outfile, 'wb') as wfh:
+            writer = csv.writer(wfh)
+            writer.writerow([c.label for c in self.active_channels]) # headers
+            for rec, rois in self.target.gem5stats.match_iter(active_sites, [self.roi_label]):
+                writer.writerow([float(rec[s]) for s in active_sites])
+        return MeasurementsCsv(outfile, self.active_channels)
+    
+    def reset(self, sites=None, kinds=None, channels=None):
+        super(Gem5PowerInstrument, self).reset(sites, kinds, channels)
+        self.target.gem5stats.reset_origin()
+