1 files changed, 85 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/GCStatsRecorder.java b/src/main/java/com/google/devtools/build/lib/runtime/GCStatsRecorder.java
new file mode 100644
index 0000000000..48e366d6b1
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/runtime/GCStatsRecorder.java
@@ -0,0 +1,85 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.runtime;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+
+import java.lang.management.GarbageCollectorMXBean;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Record GC stats for a build.
+ */
+public class GCStatsRecorder {
+
+  private final Iterable<GarbageCollectorMXBean> mxBeans;
+  private final ImmutableMap<String, GCStat> initialData;
+
+  public GCStatsRecorder(Iterable<GarbageCollectorMXBean> mxBeans) {
+    this.mxBeans = mxBeans;
+    ImmutableMap.Builder<String, GCStat> initialData = ImmutableMap.builder();
+    for (GarbageCollectorMXBean mxBean : mxBeans) {
+      String name = mxBean.getName();
+      initialData.put(name, new GCStat(name, mxBean.getCollectionCount(),
+          mxBean.getCollectionTime()));
+    }
+    this.initialData = initialData.build();
+  }
+
+  public Iterable<GCStat> getCurrentGcStats() {
+    List<GCStat> stats = new ArrayList<>();
+    for (GarbageCollectorMXBean mxBean : mxBeans) {
+      String name = mxBean.getName();
+      GCStat initStat = Preconditions.checkNotNull(initialData.get(name));
+      stats.add(new GCStat(name,
+          mxBean.getCollectionCount() - initStat.getNumCollections(),
+          mxBean.getCollectionTime() - initStat.getTotalTimeInMs()));
+    }
+    return stats;
+  }
+
+  /** Represents the garbage collections statistics for one collector (For example CMS). */
+  public static class GCStat {
+
+    private final String name;
+    private final long numCollections;
+    private final long totalTimeInMs;
+
+    public GCStat(String name, long numCollections, long totalTimeInMs) {
+      this.name = name;
+      this.numCollections = numCollections;
+      this.totalTimeInMs = totalTimeInMs;
+    }
+
+    /** Name of the Collector. For example CMS. */
+    public String getName() { return name; }
+
+    /** Number of invocations for a build. */
+    public long getNumCollections() { return numCollections; }
+
+    /**
+     * Total time spend in GC for the collector. Note that the time does need to be exclusive (aka a
+     * stop-the-world GC).
+     */
+    public long getTotalTimeInMs() { return totalTimeInMs; }
+
+    @Override
+    public String toString() {
+      return "GC time for '" + name + "' collector: " + numCollections
+          + " collections using " + totalTimeInMs + "ms";
+    }
+  }
+}