| // -*- 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 <__threading_support> |
| |
| #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 |
