Added test for perf of benchmarking

We check the time spent to run benchmarks doesn't increase with the
number of iterations.

core/src/test/kotlin/TracingCollectionRunnerTest.kt

 import com.google.common.graph.GraphBuilder
 import com.google.common.graph.MutableGraph
+import org.apache.commons.math3.stat.regression.SimpleRegression
 import org.junit.jupiter.api.*
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.ValueSource
 import org.openjdk.jmh.infra.Blackhole
 import papi.Constants
 import papi.EventSet
+import se.lth.cs.average
 import se.lth.cs.bcgen.BCBenchmarkPackage
 import se.lth.cs.papicounters.PAPICounter
 import se.lth.cs.papicounters.PapiBenchmarkAnalyzer
 import se.lth.cs.papicounters.PapiTracerRunner
 import se.lth.cs.smartmodules.tracer.Tracer
 import se.lth.cs.timing.OperationType
+import se.lth.cs.variance
 import se.lth.util.ArrayListTracer
 import java.io.ByteArrayOutputStream
 import java.io.File
 import java.io.PrintStream
+import kotlin.system.measureTimeMillis
 
 class TracingCollectionRunnerTest {
     // In this file, we will test running benchmarks with tracing collections
@@ -205,4 +209,31 @@ class TracingCollectionRunnerTest {
             Assertions.assertEquals(1, r.benchmark.numberRuns)
         }
     }
+
+    @Test
+    fun testPerformance() {
+        // TODO: Do the same, but create a lot of benchmarks!
+        val bench = BCBenchmarkPackage.LIST(12345, 1000, 0, ArrayList<Int>())
+
+        val features = listOf(PAPICounter("PAPI_TOT_CYC"), PAPICounter("PAPI_TOT_INS"))
+
+        val times = mutableListOf<Double>()
+        val max = 100
+        for (i in 0..max) {
+            val timeSpent = measureTimeMillis {
+                runner!!.runIterations(
+                    PapiBenchmarkAnalyzer.RunSpec(10, features, EventSet.create(), bench)
+                )
+            }
+            times.add(timeSpent / 1000.0)
+        }
+
+        val reg = SimpleRegression()
+        for (i in 0..max) {
+            reg.addData(i.toDouble(), times[i])
+        }
+
+        Assertions.assertEquals(0.0, reg.slope, 0.01)
+
+    }
 }
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