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