104eeddc0SDimitry Andric // -*- C++ -*- 204eeddc0SDimitry Andric //===----------------------------------------------------------------------===// 304eeddc0SDimitry Andric // 404eeddc0SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 504eeddc0SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 604eeddc0SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 704eeddc0SDimitry Andric // 804eeddc0SDimitry Andric //===----------------------------------------------------------------------===// 9bdd1243dSDimitry Andric 1004eeddc0SDimitry Andric #ifndef _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H 1104eeddc0SDimitry Andric #define _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H 1204eeddc0SDimitry Andric 1304eeddc0SDimitry Andric #include <__config> 1404eeddc0SDimitry Andric 1504eeddc0SDimitry Andric #ifndef _LIBCPP_HAS_NO_THREADS 1604eeddc0SDimitry Andric 1781ad6265SDimitry Andric # include <__chrono/duration.h> 18*0fca6ea1SDimitry Andric # include <__thread/support.h> 1904eeddc0SDimitry Andric 2004eeddc0SDimitry Andric # if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 2104eeddc0SDimitry Andric # pragma GCC system_header 2204eeddc0SDimitry Andric # endif 2304eeddc0SDimitry Andric 2404eeddc0SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 2504eeddc0SDimitry Andric 2604eeddc0SDimitry Andric struct __libcpp_timed_backoff_policy { 27cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI bool operator()(chrono::nanoseconds __elapsed) const { 2804eeddc0SDimitry Andric if (__elapsed > chrono::milliseconds(128)) 2904eeddc0SDimitry Andric __libcpp_thread_sleep_for(chrono::milliseconds(8)); 3004eeddc0SDimitry Andric else if (__elapsed > chrono::microseconds(64)) 3104eeddc0SDimitry Andric __libcpp_thread_sleep_for(__elapsed / 2); 3204eeddc0SDimitry Andric else if (__elapsed > chrono::microseconds(4)) 3304eeddc0SDimitry Andric __libcpp_thread_yield(); 34cb14a3feSDimitry Andric else { 35cb14a3feSDimitry Andric } // poll 3604eeddc0SDimitry Andric return false; 3704eeddc0SDimitry Andric } 3804eeddc0SDimitry Andric }; 3904eeddc0SDimitry Andric 4004eeddc0SDimitry Andric _LIBCPP_END_NAMESPACE_STD 4104eeddc0SDimitry Andric 4204eeddc0SDimitry Andric #endif // _LIBCPP_HAS_NO_THREADS 4304eeddc0SDimitry Andric 4404eeddc0SDimitry Andric #endif // _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H 45