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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 <__chrono/duration.h>
- # include <__thread/support.h>
- # if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
- # pragma GCC system_header
- # endif
- _LIBCPP_BEGIN_NAMESPACE_STD
- struct __libcpp_timed_backoff_policy {
- _LIBCPP_HIDE_FROM_ABI 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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