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