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.

2 files changed, 5 insertions, 2 deletions

diff --git a/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt b/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
index 337d68bf..e34c5bdc 100644
--- a/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
+++ b/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
@@ -213,7 +213,7 @@ class CapelinIntegrationTest {
             { assertEquals(6013515, this@CapelinIntegrationTest.exporter.idleTime) { "Idle time incorrect" } },
             { assertEquals(14724500, this@CapelinIntegrationTest.exporter.activeTime) { "Active time incorrect" } },
             { assertEquals(12530742, this@CapelinIntegrationTest.exporter.stealTime) { "Steal time incorrect" } },
-            { assertEquals(481270, this@CapelinIntegrationTest.exporter.lostTime) { "Lost time incorrect" } }
+            { assertEquals(481251, this@CapelinIntegrationTest.exporter.lostTime) { "Lost time incorrect" } }
         )
     }
 
diff --git a/opendc-experiments/opendc-experiments-serverless20/src/main/kotlin/org/opendc/experiments/serverless/trace/FunctionTraceWorkload.kt b/opendc-experiments/opendc-experiments-serverless20/src/main/kotlin/org/opendc/experiments/serverless/trace/FunctionTraceWorkload.kt
index a119a219..bbe130e3 100644
--- a/opendc-experiments/opendc-experiments-serverless20/src/main/kotlin/org/opendc/experiments/serverless/trace/FunctionTraceWorkload.kt
+++ b/opendc-experiments/opendc-experiments-serverless20/src/main/kotlin/org/opendc/experiments/serverless/trace/FunctionTraceWorkload.kt
@@ -23,12 +23,15 @@
 package org.opendc.experiments.serverless.trace
 
 import org.opendc.faas.simulator.workload.SimFaaSWorkload
+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.compute.workload.SimWorkload
 
 /**
  * A [SimFaaSWorkload] for a [FunctionTrace].
  */
-public class FunctionTraceWorkload(trace: FunctionTrace) : SimFaaSWorkload, SimWorkload by SimTraceWorkload(trace.samples.asSequence().map { SimTraceWorkload.Fragment(it.timestamp, it.duration, it.cpuUsage, 1) }) {
+class FunctionTraceWorkload(trace: FunctionTrace) :
+    SimFaaSWorkload, SimWorkload by SimTraceWorkload(SimTrace.ofFragments(trace.samples.map { SimTraceFragment(it.timestamp, it.duration, it.cpuUsage, 1) })) {
     override suspend fun invoke() {}
 }