| Jeff Thompson | f7d4994 | 2013-08-01 16:47:40 -0700 | [diff] [blame^] | 1 | #ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED |
| 2 | #define BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED |
| 3 | |
| 4 | // MS compatible compilers support #pragma once |
| 5 | |
| 6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| 7 | # pragma once |
| 8 | #endif |
| 9 | |
| 10 | // |
| 11 | // yield_k.hpp |
| 12 | // |
| 13 | // Copyright (c) 2008 Peter Dimov |
| 14 | // |
| 15 | // void yield( unsigned k ); |
| 16 | // |
| 17 | // Typical use: |
| 18 | // |
| 19 | // for( unsigned k = 0; !try_lock(); ++k ) yield( k ); |
| 20 | // |
| 21 | // Distributed under the Boost Software License, Version 1.0. |
| 22 | // See accompanying file LICENSE_1_0.txt or copy at |
| 23 | // http://www.boost.org/LICENSE_1_0.txt |
| 24 | // |
| 25 | |
| 26 | #include <boost/config.hpp> |
| 27 | |
| 28 | // BOOST_SMT_PAUSE |
| 29 | |
| 30 | #if defined(_MSC_VER) && _MSC_VER >= 1310 && ( defined(_M_IX86) || defined(_M_X64) ) |
| 31 | |
| 32 | extern "C" void _mm_pause(); |
| 33 | #pragma intrinsic( _mm_pause ) |
| 34 | |
| 35 | #define BOOST_SMT_PAUSE _mm_pause(); |
| 36 | |
| 37 | #elif defined(__GNUC__) && ( defined(__i386__) || defined(__x86_64__) ) |
| 38 | |
| 39 | #define BOOST_SMT_PAUSE __asm__ __volatile__( "rep; nop" : : : "memory" ); |
| 40 | |
| 41 | #endif |
| 42 | |
| 43 | // |
| 44 | |
| 45 | #if defined( WIN32 ) || defined( _WIN32 ) || defined( __WIN32__ ) || defined( __CYGWIN__ ) |
| 46 | |
| 47 | #if defined( BOOST_USE_WINDOWS_H ) |
| 48 | # include <windows.h> |
| 49 | #endif |
| 50 | |
| 51 | namespace ndnboost |
| 52 | { |
| 53 | |
| 54 | namespace detail |
| 55 | { |
| 56 | |
| 57 | #if !defined( BOOST_USE_WINDOWS_H ) |
| 58 | extern "C" void __stdcall Sleep( unsigned long ms ); |
| 59 | #endif |
| 60 | |
| 61 | inline void yield( unsigned k ) |
| 62 | { |
| 63 | if( k < 4 ) |
| 64 | { |
| 65 | } |
| 66 | #if defined( BOOST_SMT_PAUSE ) |
| 67 | else if( k < 16 ) |
| 68 | { |
| 69 | BOOST_SMT_PAUSE |
| 70 | } |
| 71 | #endif |
| 72 | else if( k < 32 ) |
| 73 | { |
| 74 | Sleep( 0 ); |
| 75 | } |
| 76 | else |
| 77 | { |
| 78 | Sleep( 1 ); |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | } // namespace detail |
| 83 | |
| 84 | } // namespace ndnboost |
| 85 | |
| 86 | #elif defined( BOOST_HAS_PTHREADS ) |
| 87 | |
| 88 | #include <sched.h> |
| 89 | #include <time.h> |
| 90 | |
| 91 | namespace ndnboost |
| 92 | { |
| 93 | |
| 94 | namespace detail |
| 95 | { |
| 96 | |
| 97 | inline void yield( unsigned k ) |
| 98 | { |
| 99 | if( k < 4 ) |
| 100 | { |
| 101 | } |
| 102 | #if defined( BOOST_SMT_PAUSE ) |
| 103 | else if( k < 16 ) |
| 104 | { |
| 105 | BOOST_SMT_PAUSE |
| 106 | } |
| 107 | #endif |
| 108 | else if( k < 32 || k & 1 ) |
| 109 | { |
| 110 | sched_yield(); |
| 111 | } |
| 112 | else |
| 113 | { |
| 114 | // g++ -Wextra warns on {} or {0} |
| 115 | struct timespec rqtp = { 0, 0 }; |
| 116 | |
| 117 | // POSIX says that timespec has tv_sec and tv_nsec |
| 118 | // But it doesn't guarantee order or placement |
| 119 | |
| 120 | rqtp.tv_sec = 0; |
| 121 | rqtp.tv_nsec = 1000; |
| 122 | |
| 123 | nanosleep( &rqtp, 0 ); |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | } // namespace detail |
| 128 | |
| 129 | } // namespace ndnboost |
| 130 | |
| 131 | #else |
| 132 | |
| 133 | namespace ndnboost |
| 134 | { |
| 135 | |
| 136 | namespace detail |
| 137 | { |
| 138 | |
| 139 | inline void yield( unsigned ) |
| 140 | { |
| 141 | } |
| 142 | |
| 143 | } // namespace detail |
| 144 | |
| 145 | } // namespace ndnboost |
| 146 | |
| 147 | #endif |
| 148 | |
| 149 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_YIELD_K_HPP_INCLUDED |