Benchmark the OpenHashMap memory usage.

Also add sbteclipse to the benchmark project.

4 files changed, 35 insertions, 11 deletions

diff --git a/test/benchmarks/.gitignore b/test/benchmarks/.gitignore
index 6e3ddad6d2..ce4d893417 100644
--- a/test/benchmarks/.gitignore
+++ b/test/benchmarks/.gitignore
@@ -4,3 +4,11 @@
 
 # what appears to be a Scala IDE-generated file
 .cache-main
+
+# standard Eclipse output directory
+/bin/
+
+# sbteclipse-generated Eclipse files
+/.classpath
+/.project
+/.settings/
diff --git a/test/benchmarks/build.sbt b/test/benchmarks/build.sbt
index 92a5fce177..2959e4986a 100644
--- a/test/benchmarks/build.sbt
+++ b/test/benchmarks/build.sbt
@@ -1,8 +1,11 @@
 scalaHome := Some(file("../../build/pack"))
+scalaVersion := "2.11.8"
+scalacOptions += "-feature"
 
 lazy val root = (project in file(".")).
   enablePlugins(JmhPlugin).
   settings(
     name := "test-benchmarks",
-    version := "0.0.1"
+    version := "0.0.1",
+	libraryDependencies += "org.openjdk.jol" % "jol-core" % "0.4"
   )
diff --git a/test/benchmarks/project/plugins.sbt b/test/benchmarks/project/plugins.sbt
index f5319fb187..e11aa29f3b 100644
--- a/test/benchmarks/project/plugins.sbt
+++ b/test/benchmarks/project/plugins.sbt
@@ -1 +1,2 @@
+addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "4.0.0")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.2.6")
diff --git a/test/benchmarks/src/main/scala/scala/collection/mutable/OpenHashMapBenchmark.scala b/test/benchmarks/src/main/scala/scala/collection/mutable/OpenHashMapBenchmark.scala
index 73ab5e40d0..13be9e6206 100644
--- a/test/benchmarks/src/main/scala/scala/collection/mutable/OpenHashMapBenchmark.scala
+++ b/test/benchmarks/src/main/scala/scala/collection/mutable/OpenHashMapBenchmark.scala
@@ -4,6 +4,9 @@ import java.util.concurrent.TimeUnit
 import org.openjdk.jmh.annotations._
 import org.openjdk.jmh.infra.Blackhole
 import org.openjdk.jmh.infra.BenchmarkParams
+import org.openjdk.jol.info.GraphLayout
+import org.openjdk.jol.info.GraphWalker
+import org.openjdk.jol.info.GraphVisitor
 
 /** Utilities for the [[OpenHashMapBenchmark]].
   * 
@@ -15,9 +18,11 @@ private object OpenHashMapBenchmark {
     * 
     * Provides an array of adequately-sized, empty maps to each invocation,
     * so that hash table allocation won't be done during measurement.
-    * 
-    * Empties the map and performs a GC after every invocation,
+    * Provides enough maps to make each invocation long enough to avoid timing artifacts.
+    * Performs a GC after re-creating the empty maps before every invocation,
     * so that only the GCs caused by the invocation contribute to the measurement.
+    * 
+    * Records the memory used by all the maps in the last invocation of each iteration.
     */
   @State(Scope.Thread)
   @AuxCounters
@@ -28,24 +33,25 @@ private object OpenHashMapBenchmark {
     /** Minimum number of nanoseconds per invocation, so as to avoid timing artifacts. */
     private[this] val minNanosPerInvocation = 1000000  // one millisecond
 
-    /** The minimum number of `put()` calls to make per invocation, so as to avoid timing artifacts. */
-    private[this] val minPutsPerInvocation = minNanosPerInvocation / nanosPerPut
-
     /** Size of the maps created in this trial. */
     private[this] var size: Int = _
 
-    /** Number of maps created in each invocation; the size of `maps`. */
-    private[this] var n: Int = _
+    /** Total number of entries in all of the `maps` combined. */
+    var mapEntries: Int = _
 
     /** Number of operations performed in the current invocation. */
     var operations: Int = _
 
+    /** Bytes of memory used in the object graphs of all the maps. */
+    var memory: Long = _
+
     var maps: Array[OpenHashMap[Int,Int]] = null
 
     @Setup
     def threadSetup(params: BenchmarkParams) {
       size = params.getParam("size").toInt
-      n = math.ceil(minPutsPerInvocation / size).toInt
+      val n = math.ceil(minNanosPerInvocation / (nanosPerPut * size)).toInt
+      mapEntries = size * n
       maps = new Array(n)
     }
 
@@ -56,10 +62,16 @@ private object OpenHashMapBenchmark {
 
     @Setup(Level.Invocation)
     def setup {
-      for (i <- 0 until n) maps(i) = new OpenHashMap[Int,Int](size)
-      operations += size * n
+      for (i <- 0 until maps.length) maps(i) = new OpenHashMap[Int,Int](size)
+      operations += mapEntries
       System.gc()  // clean up after last invocation
     }
+
+    @TearDown(Level.Iteration)
+    def iterationTeardown {
+      // limit to smaller cases to avoid OOM
+      memory = if (mapEntries <= 1000000) GraphLayout.parseInstance(maps(0), maps.tail).totalSize else 0
+    }
   }
 
   /** State container for the `get()` bulk calling tests.