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diff --git a/Source/JavaScriptCore/bytecode/SuperSampler.cpp b/Source/JavaScriptCore/bytecode/SuperSampler.cpp
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+++ b/Source/JavaScriptCore/bytecode/SuperSampler.cpp
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+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "SuperSampler.h"
+
+#include "MacroAssembler.h"
+#include "Options.h"
+#include <wtf/CurrentTime.h>
+#include <wtf/DataLog.h>
+#include <wtf/Lock.h>
+#include <wtf/Threading.h>
+
+namespace JSC {
+
+volatile uint32_t g_superSamplerCount;
+
+static StaticLock lock;
+static double in;
+static double out;
+
+void initializeSuperSampler()
+{
+    if (!Options::useSuperSampler())
+        return;
+
+    createThread(
+        "JSC Super Sampler",
+        [] () {
+            const int sleepQuantum = 10;
+            const int printingPeriod = 1000;
+            for (;;) {
+                for (int ms = 0; ms < printingPeriod; ms += sleepQuantum) {
+                    {
+                        LockHolder locker(lock);
+                        if (g_superSamplerCount)
+                            in++;
+                        else
+                            out++;
+                    }
+                    sleepMS(sleepQuantum);
+                }
+                printSuperSamplerState();
+                if (static_cast<int32_t>(g_superSamplerCount) < 0)
+                    dataLog("WARNING: Super sampler undercount detected!\n");
+            }
+        });
+}
+
+void resetSuperSamplerState()
+{
+    LockHolder locker(lock);
+    in = 0;
+    out = 0;
+}
+
+void printSuperSamplerState()
+{
+    if (!Options::useSuperSampler())
+        return;
+
+    LockHolder locker(lock);
+    double percentage = 100.0 * in / (in + out);
+    if (percentage != percentage)
+        percentage = 0.0;
+    dataLog("Percent time behind super sampler flag: ", percentage, "\n");
+}
+
+} // namespace JSC
+