Chris@16: #ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED
Chris@16: #define BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED
Chris@16: 
Chris@16: // MS compatible compilers support #pragma once
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: //
Chris@16: //  yield_k.hpp
Chris@16: //
Chris@16: //  Copyright (c) 2008 Peter Dimov
Chris@101: //  Copyright (c) Microsoft Corporation 2014
Chris@16: //
Chris@16: //  void yield( unsigned k );
Chris@16: //
Chris@16: //  Typical use:
Chris@16: //
Chris@16: //  for( unsigned k = 0; !try_lock(); ++k ) yield( k );
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0.
Chris@16: //  See accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt
Chris@16: //
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@101: #include <boost/predef.h>
Chris@101: 
Chris@101: #if BOOST_PLAT_WINDOWS_RUNTIME
Chris@101: #include <thread>
Chris@101: #endif
Chris@16: 
Chris@16: // BOOST_SMT_PAUSE
Chris@16: 
Chris@16: #if defined(_MSC_VER) && _MSC_VER >= 1310 && ( defined(_M_IX86) || defined(_M_X64) )
Chris@16: 
Chris@16: extern "C" void _mm_pause();
Chris@16: 
Chris@16: #define BOOST_SMT_PAUSE _mm_pause();
Chris@16: 
Chris@16: #elif defined(__GNUC__) && ( defined(__i386__) || defined(__x86_64__) )
Chris@16: 
Chris@16: #define BOOST_SMT_PAUSE __asm__ __volatile__( "rep; nop" : : : "memory" );
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: //
Chris@16: 
Chris@16: #if defined( WIN32 ) || defined( _WIN32 ) || defined( __WIN32__ ) || defined( __CYGWIN__ )
Chris@16: 
Chris@16: #if defined( BOOST_USE_WINDOWS_H )
Chris@16: # include <windows.h>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@101: #if !defined( BOOST_USE_WINDOWS_H ) && !BOOST_PLAT_WINDOWS_RUNTIME
Chris@16:   extern "C" void __stdcall Sleep( unsigned long ms );
Chris@16: #endif
Chris@16: 
Chris@16: inline void yield( unsigned k )
Chris@16: {
Chris@16:     if( k < 4 )
Chris@16:     {
Chris@16:     }
Chris@16: #if defined( BOOST_SMT_PAUSE )
Chris@16:     else if( k < 16 )
Chris@16:     {
Chris@16:         BOOST_SMT_PAUSE
Chris@16:     }
Chris@16: #endif
Chris@101: #if !BOOST_PLAT_WINDOWS_RUNTIME
Chris@16:     else if( k < 32 )
Chris@16:     {
Chris@16:         Sleep( 0 );
Chris@16:     }
Chris@16:     else
Chris@16:     {
Chris@16:         Sleep( 1 );
Chris@16:     }
Chris@101: #else
Chris@101:     else
Chris@101:     {
Chris@101:         // Sleep isn't supported on the Windows Runtime.
Chris@101:         std::this_thread::yield();
Chris@101:     }
Chris@101: #endif
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #elif defined( BOOST_HAS_PTHREADS )
Chris@16: 
Chris@101: #ifndef _AIX
Chris@16: #include <sched.h>
Chris@101: #else
Chris@101:    // AIX's sched.h defines ::var which sometimes conflicts with Lambda's var
Chris@101:        extern "C" int sched_yield(void);
Chris@101: #endif
Chris@101: 
Chris@16: #include <time.h>
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: inline void yield( unsigned k )
Chris@16: {
Chris@16:     if( k < 4 )
Chris@16:     {
Chris@16:     }
Chris@16: #if defined( BOOST_SMT_PAUSE )
Chris@16:     else if( k < 16 )
Chris@16:     {
Chris@16:         BOOST_SMT_PAUSE
Chris@16:     }
Chris@16: #endif
Chris@16:     else if( k < 32 || k & 1 )
Chris@16:     {
Chris@16:         sched_yield();
Chris@16:     }
Chris@16:     else
Chris@16:     {
Chris@16:         // g++ -Wextra warns on {} or {0}
Chris@16:         struct timespec rqtp = { 0, 0 };
Chris@16: 
Chris@16:         // POSIX says that timespec has tv_sec and tv_nsec
Chris@16:         // But it doesn't guarantee order or placement
Chris@16: 
Chris@16:         rqtp.tv_sec = 0;
Chris@16:         rqtp.tv_nsec = 1000;
Chris@16: 
Chris@16:         nanosleep( &rqtp, 0 );
Chris@16:     }
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: inline void yield( unsigned )
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: #endif // #ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED