--- /dev/null	2019-01-28 17:45:11.000000000 +0800
+++ new/src/cpu/x86/vm/rdtsc_x86.cpp	2019-01-28 17:45:11.000000000 +0800
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "rdtsc_x86.hpp"
+#include "runtime/thread.inline.hpp"
+#include "vm_version_ext_x86.hpp"
+
+// The following header contains the implementations of rdtsc()
+#ifdef TARGET_OS_ARCH_linux_x86
+#include "os_linux_x86.inline.hpp"
+#endif
+
+static jlong baseline_counter = 0;
+static bool rdtsc_elapsed_counter_enabled = false;
+static jlong tsc_frequency = 0;
+
+static jlong set_baseline_counter() {
+  assert(0 == baseline_counter, "invariant");
+  baseline_counter = os::rdtsc();
+  return baseline_counter;
+}
+
+// Base loop to estimate ticks frequency for tsc counter from user mode.
+// Volatiles and sleep() are used to prevent compiler from applying optimizations.
+static void do_time_measurements(volatile jlong& time_base,
+                                 volatile jlong& time_fast,
+                                 volatile jlong& time_base_elapsed,
+                                 volatile jlong& time_fast_elapsed) {
+  static const unsigned int FT_SLEEP_MILLISECS = 1;
+  const unsigned int loopcount = 3;
+
+  volatile jlong start = 0;
+  volatile jlong fstart = 0;
+  volatile jlong end = 0;
+  volatile jlong fend = 0;
+
+  // Figure out the difference between rdtsc and os provided timer.
+  // base algorithm adopted from JRockit.
+  for (unsigned int times = 0; times < loopcount; times++) {
+    start = os::elapsed_counter();
+    OrderAccess::fence();
+    fstart = os::rdtsc();
+
+    // use sleep to prevent compiler from optimizing
+    os::sleep(Thread::current(), FT_SLEEP_MILLISECS, true);
+
+    end = os::elapsed_counter();
+    OrderAccess::fence();
+    fend = os::rdtsc();
+
+    time_base += end - start;
+    time_fast += fend - fstart;
+
+    // basis for calculating the os tick start
+    // to fast time tick start offset
+    time_base_elapsed += end;
+    time_fast_elapsed += (fend - baseline_counter);
+  }
+
+  time_base /= loopcount;
+  time_fast /= loopcount;
+  time_base_elapsed /= loopcount;
+  time_fast_elapsed /= loopcount;
+}
+
+static jlong initialize_frequency() {
+  assert(0 == tsc_frequency, "invariant");
+  assert(0 == baseline_counter, "invariant");
+  jlong initial_counter = set_baseline_counter();
+  if (initial_counter == 0) {
+    return 0;
+  }
+  // os time frequency
+  static double os_freq = (double)os::elapsed_frequency();
+  assert(os_freq > 0, "os_elapsed frequency corruption!");
+
+  double tsc_freq = .0;
+  double os_to_tsc_conv_factor = 1.0;
+
+  // if platform supports invariant tsc,
+  // apply higher resolution and granularity for conversion calculations
+  if (VM_Version_Ext::supports_tscinv_ext()) {
+    // for invariant tsc platforms, take the maximum qualified cpu frequency
+    tsc_freq = (double)VM_Version_Ext::maximum_qualified_cpu_frequency();
+    os_to_tsc_conv_factor = tsc_freq / os_freq;
+  } else {
+    // for non-trusted platforms, use measurements to estimate
+    // a conversion factor and the tsc frequency
+
+    volatile jlong time_base = 0;
+    volatile jlong time_fast = 0;
+    volatile jlong time_base_elapsed = 0;
+    volatile jlong time_fast_elapsed = 0;
+
+    // do measurements to get base data
+    // on os timer and fast ticks tsc time relation.
+    do_time_measurements(time_base, time_fast, time_base_elapsed, time_fast_elapsed);
+
+    // if invalid measurements, cannot proceed
+    if (time_fast == 0 || time_base == 0) {
+      return 0;
+    }
+
+    os_to_tsc_conv_factor = (double)time_fast / (double)time_base;
+    if (os_to_tsc_conv_factor > 1) {
+      // estimate on tsc counter frequency
+      tsc_freq = os_to_tsc_conv_factor * os_freq;
+    }
+  }
+
+  if ((tsc_freq < 0) || (tsc_freq > 0 && tsc_freq <= os_freq) || (os_to_tsc_conv_factor <= 1)) {
+    // safer to run with normal os time
+    tsc_freq = .0;
+  }
+
+  // frequency of the tsc_counter
+  return (jlong)tsc_freq;
+}
+
+static bool initialize_elapsed_counter() {
+  tsc_frequency = initialize_frequency();
+  return tsc_frequency != 0 && baseline_counter != 0;
+}
+
+static bool ergonomics() {
+  const bool invtsc_support = Rdtsc::is_supported();
+  if (FLAG_IS_DEFAULT(UseFastUnorderedTimeStamps) && invtsc_support) {
+    FLAG_SET_ERGO(bool, UseFastUnorderedTimeStamps, true);
+  }
+
+  bool ft_enabled = UseFastUnorderedTimeStamps && invtsc_support;
+
+  if (!ft_enabled) {
+    if (UseFastUnorderedTimeStamps && VM_Version::supports_tsc()) {
+      warning("\nThe hardware does not support invariant tsc (INVTSC) register and/or cannot guarantee tsc synchronization between sockets at startup.\n"\
+        "Values returned via rdtsc() are not guaranteed to be accurate, esp. when comparing values from cross sockets reads. Enabling UseFastUnorderedTimeStamps on non-invariant tsc hardware should be considered experimental.\n");
+      ft_enabled = true;
+    }
+  }
+
+  if (!ft_enabled) {
+    // Warn if unable to support command-line flag
+    if (UseFastUnorderedTimeStamps && !VM_Version::supports_tsc()) {
+      warning("Ignoring UseFastUnorderedTimeStamps, hardware does not support normal tsc");
+    }
+  }
+
+  return ft_enabled;
+}
+
+bool Rdtsc::is_supported() {
+  return VM_Version_Ext::supports_tscinv_ext();
+}
+
+bool Rdtsc::is_elapsed_counter_enabled() {
+  return rdtsc_elapsed_counter_enabled;
+}
+
+jlong Rdtsc::frequency() {
+  return tsc_frequency;
+}
+
+jlong Rdtsc::elapsed_counter() {
+  return os::rdtsc() - baseline_counter;
+}
+
+jlong Rdtsc::raw() {
+  return os::rdtsc();
+}
+
+bool Rdtsc::initialize() {
+  static bool initialized = false;
+  if (!initialized) {
+    assert(!rdtsc_elapsed_counter_enabled, "invariant");
+    VM_Version_Ext::initialize();
+    assert(0 == tsc_frequency, "invariant");
+    assert(0 == baseline_counter, "invariant");
+    bool result = initialize_elapsed_counter(); // init hw
+    if (result) {
+      result = ergonomics(); // check logical state
+    }
+    rdtsc_elapsed_counter_enabled = result;
+    initialized = true;
+  }
+  return rdtsc_elapsed_counter_enabled;
+}