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44 lines
1.3 KiB
C++
44 lines
1.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H
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#define _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H
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#include <__config>
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#ifndef _LIBCPP_HAS_NO_THREADS
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# include <__chrono/duration.h>
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# include <__thread/support.h>
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# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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# endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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struct __libcpp_timed_backoff_policy {
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_LIBCPP_HIDE_FROM_ABI bool operator()(chrono::nanoseconds __elapsed) const {
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if (__elapsed > chrono::milliseconds(128))
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__libcpp_thread_sleep_for(chrono::milliseconds(8));
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else if (__elapsed > chrono::microseconds(64))
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__libcpp_thread_sleep_for(__elapsed / 2);
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else if (__elapsed > chrono::microseconds(4))
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__libcpp_thread_yield();
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else {
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} // poll
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return false;
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}
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};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_HAS_NO_THREADS
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#endif // _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H
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