merge: Performance improvements for flow engine

This pull request applies multiple performance improvements for the flow engine and 
compute simulator.

* Optimize SimTraceWorkload (by storing fragments using several arrays)
* Skip fair-share algorithm if capacity remaining 
* Count interference for multiplexer inputs 
* Simplify FlowSink implementation 
* Do not update outputs if rate is unchanged
* Eliminate ArrayList iteration overhead 
* Optimize clock storage
* Specialize FlowEngine queues
* Eliminate clock access in hot path

**Breaking API Changes**

* `SimTraceWorkload` now accepts a `SimTrace` as parameter. This trace can be constructed using fragments or directly using builder class. Internally, the trace is now stored using several arrays.

1 files changed, 17 insertions, 15 deletions

diff --git a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
index 26089b6d..a0ff9228 100644
--- a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
+++ b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
@@ -39,6 +39,8 @@ import org.opendc.simulator.compute.model.MachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
 import org.opendc.simulator.compute.model.ProcessingNode
 import org.opendc.simulator.compute.model.ProcessingUnit
+import org.opendc.simulator.compute.workload.SimTrace
+import org.opendc.simulator.compute.workload.SimTraceFragment
 import org.opendc.simulator.compute.workload.SimTraceWorkload
 import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.FlowEngine
@@ -105,11 +107,11 @@ internal class SimHostTest {
             emptyMap(),
             mapOf(
                 "workload" to SimTraceWorkload(
-                    sequenceOf(
-                        SimTraceWorkload.Fragment(0, duration * 1000, 2 * 28.0, 2),
-                        SimTraceWorkload.Fragment(duration * 1000, duration * 1000, 2 * 3500.0, 2),
-                        SimTraceWorkload.Fragment(duration * 2000, duration * 1000, 0.0, 2),
-                        SimTraceWorkload.Fragment(duration * 3000, duration * 1000, 2 * 183.0, 2)
+                    SimTrace.ofFragments(
+                        SimTraceFragment(0, duration * 1000, 2 * 28.0, 2),
+                        SimTraceFragment(duration * 1000, duration * 1000, 2 * 3500.0, 2),
+                        SimTraceFragment(duration * 2000, duration * 1000, 0.0, 2),
+                        SimTraceFragment(duration * 3000, duration * 1000, 2 * 183.0, 2)
                     ),
                     offset = 1
                 )
@@ -121,11 +123,11 @@ internal class SimHostTest {
             emptyMap(),
             mapOf(
                 "workload" to SimTraceWorkload(
-                    sequenceOf(
-                        SimTraceWorkload.Fragment(0, duration * 1000, 2 * 28.0, 2),
-                        SimTraceWorkload.Fragment(duration * 1000, duration * 1000, 2 * 3100.0, 2),
-                        SimTraceWorkload.Fragment(duration * 2000, duration * 1000, 0.0, 2),
-                        SimTraceWorkload.Fragment(duration * 3000, duration * 1000, 2 * 73.0, 2)
+                    SimTrace.ofFragments(
+                        SimTraceFragment(0, duration * 1000, 2 * 28.0, 2),
+                        SimTraceFragment(duration * 1000, duration * 1000, 2 * 3100.0, 2),
+                        SimTraceFragment(duration * 2000, duration * 1000, 0.0, 2),
+                        SimTraceFragment(duration * 3000, duration * 1000, 2 * 73.0, 2)
                     ),
                     offset = 1
                 )
@@ -217,11 +219,11 @@ internal class SimHostTest {
             emptyMap(),
             mapOf(
                 "workload" to SimTraceWorkload(
-                    sequenceOf(
-                        SimTraceWorkload.Fragment(0, duration * 1000, 2 * 28.0, 2),
-                        SimTraceWorkload.Fragment(duration * 1000L, duration * 1000, 2 * 3500.0, 2),
-                        SimTraceWorkload.Fragment(duration * 2000L, duration * 1000, 0.0, 2),
-                        SimTraceWorkload.Fragment(duration * 3000L, duration * 1000, 2 * 183.0, 2)
+                    SimTrace.ofFragments(
+                        SimTraceFragment(0, duration * 1000, 2 * 28.0, 2),
+                        SimTraceFragment(duration * 1000L, duration * 1000, 2 * 3500.0, 2),
+                        SimTraceFragment(duration * 2000L, duration * 1000, 0.0, 2),
+                        SimTraceFragment(duration * 3000L, duration * 1000, 2 * 183.0, 2)
                     ),
                     offset = 1
                 )