merge: Fix distributed strategy for TensorFlow experiment (#89)

This pull request fixes an issue where the distributed strategies for the 
TensorFlow experiments did not work correctly.

## Implementation Notes :hammer_and_pick:

* Limit growth rate for trace construction
* Derive device statistics directly from SimMachine 
* Always recompute power usage when a `SImBareMetalMachine` converges
* Add a test case for `MirroredStrategy`

1 files changed, 3 insertions, 15 deletions

diff --git a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
index 90350142..2c79da02 100644
--- a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
+++ b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
@@ -68,13 +68,6 @@ public class SimTFDevice(
     )
 
     /**
-     * Metrics collected by the device.
-     */
-    private var _resourceUsage = 0.0
-    private var _powerUsage = 0.0
-    private var _energyUsage = 0.0
-
-    /**
      * The workload that will be run by the device.
      */
     private val workload = object : SimWorkload, FlowSource {
@@ -121,7 +114,7 @@ public class SimTFDevice(
             ctx = conn
             capacity = conn.capacity
             lastPull = now
-            conn.shouldSourceConverge = true
+            conn.shouldSourceConverge = false
         }
 
         override fun onPull(conn: FlowConnection, now: Long): Long {
@@ -156,12 +149,6 @@ public class SimTFDevice(
                 Long.MAX_VALUE
             }
         }
-
-        override fun onConverge(conn: FlowConnection, now: Long) {
-            _resourceUsage = conn.rate
-            _powerUsage = machine.powerUsage
-            _energyUsage = machine.energyUsage
-        }
     }
 
     init {
@@ -183,7 +170,8 @@ public class SimTFDevice(
     }
 
     override fun getDeviceStats(): TFDeviceStats {
-        return TFDeviceStats(_resourceUsage, _powerUsage, _energyUsage)
+        val resourceUsage = machine.cpus.sumOf { it.rate }
+        return TFDeviceStats(resourceUsage, machine.powerUsage, machine.energyUsage)
     }
 
     override fun close() {