jdk

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/*
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 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "runtime/os.hpp"
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#include "utilities/ostream.hpp"
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#include "utilities/spinYield.hpp"
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SpinYield::SpinYield(uint spin_limit, uint yield_limit, uint sleep_ns) :
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  _sleep_time(),
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  _spins(0),
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  _yields(0),
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  _spin_limit(os::is_MP() ? spin_limit : 0),
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  _yield_limit(yield_limit),
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  _sleep_ns(sleep_ns)
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{}
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void SpinYield::yield_or_sleep() {
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  if (_yields < _yield_limit) {
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    ++_yields;
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    os::naked_yield();
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  } else {
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    Ticks sleep_start = Ticks::now();
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    os::naked_short_nanosleep(_sleep_ns);
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    _sleep_time += Ticks::now() - sleep_start;
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  }
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}
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static const char* print_separator(outputStream* s, const char* separator) {
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  s->print("%s", separator);
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  return ", ";
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}
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void SpinYield::report(outputStream* s) const {
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  const char* initial_separator = "";
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  const char* separator = initial_separator;
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  if (_spins > 0) {             // Report spins, if any.
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    separator = print_separator(s, separator);
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    s->print("spins = %u", _spins);
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  }
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  if (_yields > 0) {            // Report yields, if any.
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    separator = print_separator(s, separator);
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    s->print("yields = %u", _yields);
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  }
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  if (_sleep_time.value() != 0) { // Report sleep duration, if slept.
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    separator = print_separator(s, separator);
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    s->print("sleep = " UINT64_FORMAT " usecs",
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             _sleep_time.microseconds());
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  }
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  if (separator == initial_separator) {
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    s->print("no waiting");
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  }
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}
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