#ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED | |
#define BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED | |
// MS compatible compilers support #pragma once | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
// | |
// yield_k.hpp | |
// | |
// Copyright (c) 2008 Peter Dimov | |
// | |
// void yield( unsigned k ); | |
// | |
// Typical use: | |
// | |
// for( unsigned k = 0; !try_lock(); ++k ) yield( k ); | |
// | |
// Distributed under the Boost Software License, Version 1.0. | |
// See accompanying file LICENSE_1_0.txt or copy at | |
// http://www.boost.org/LICENSE_1_0.txt | |
// | |
#include <boost/config.hpp> | |
// BOOST_SMT_PAUSE | |
#if defined(_MSC_VER) && _MSC_VER >= 1310 && ( defined(_M_IX86) || defined(_M_X64) ) | |
extern "C" void _mm_pause(); | |
#pragma intrinsic( _mm_pause ) | |
#define BOOST_SMT_PAUSE _mm_pause(); | |
#elif defined(__GNUC__) && ( defined(__i386__) || defined(__x86_64__) ) | |
#define BOOST_SMT_PAUSE __asm__ __volatile__( "rep; nop" : : : "memory" ); | |
#endif | |
// | |
#if defined( WIN32 ) || defined( _WIN32 ) || defined( __WIN32__ ) || defined( __CYGWIN__ ) | |
#if defined( BOOST_USE_WINDOWS_H ) | |
# include <windows.h> | |
#endif | |
namespace boost | |
{ | |
namespace detail | |
{ | |
#if !defined( BOOST_USE_WINDOWS_H ) | |
extern "C" void __stdcall Sleep( unsigned long ms ); | |
#endif | |
inline void yield( unsigned k ) | |
{ | |
if( k < 4 ) | |
{ | |
} | |
#if defined( BOOST_SMT_PAUSE ) | |
else if( k < 16 ) | |
{ | |
BOOST_SMT_PAUSE | |
} | |
#endif | |
else if( k < 32 ) | |
{ | |
Sleep( 0 ); | |
} | |
else | |
{ | |
Sleep( 1 ); | |
} | |
} | |
} // namespace detail | |
} // namespace boost | |
#elif defined( BOOST_HAS_PTHREADS ) | |
#include <sched.h> | |
#include <time.h> | |
namespace boost | |
{ | |
namespace detail | |
{ | |
inline void yield( unsigned k ) | |
{ | |
if( k < 4 ) | |
{ | |
} | |
#if defined( BOOST_SMT_PAUSE ) | |
else if( k < 16 ) | |
{ | |
BOOST_SMT_PAUSE | |
} | |
#endif | |
else if( k < 32 || k & 1 ) | |
{ | |
sched_yield(); | |
} | |
else | |
{ | |
// g++ -Wextra warns on {} or {0} | |
struct timespec rqtp = { 0, 0 }; | |
// POSIX says that timespec has tv_sec and tv_nsec | |
// But it doesn't guarantee order or placement | |
rqtp.tv_sec = 0; | |
rqtp.tv_nsec = 1000; | |
nanosleep( &rqtp, 0 ); | |
} | |
} | |
} // namespace detail | |
} // namespace boost | |
#else | |
namespace boost | |
{ | |
namespace detail | |
{ | |
inline void yield( unsigned ) | |
{ | |
} | |
} // namespace detail | |
} // namespace boost | |
#endif | |
#endif // #ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED |