diff --git a/include/boost/smart_ptr/detail/sp_thread_pause.hpp b/include/boost/smart_ptr/detail/sp_thread_pause.hpp
index 2cddd90..2bb7d39 100644
--- a/include/boost/smart_ptr/detail/sp_thread_pause.hpp
+++ b/include/boost/smart_ptr/detail/sp_thread_pause.hpp
@@ -1,51 +1,20 @@
 #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_PAUSE_HPP_INCLUDED
 #define BOOST_SMART_PTR_DETAIL_SP_THREAD_PAUSE_HPP_INCLUDED
 
-// MS compatible compilers support #pragma once
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1020)
-# pragma once
-#endif
-
-// boost/smart_ptr/detail/sp_thread_pause.hpp
-//
-// inline void bost::detail::sp_thread_pause();
-//
-//   Emits a "pause" instruction.
-//
-// Copyright 2008, 2020 Peter Dimov
-// Distributed under the Boost Software License, Version 1.0
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
-#if defined(_MSC_VER) && _MSC_VER >= 1310 && ( defined(_M_IX86) || defined(_M_X64) ) && !defined(__c2__)
-
-extern "C" void _mm_pause();
-
-#define BOOST_SP_PAUSE _mm_pause();
-
-#elif defined(__GNUC__) && ( defined(__i386__) || defined(__x86_64__) )
-
-#define BOOST_SP_PAUSE __asm__ __volatile__( "rep; nop" : : : "memory" );
-
-#else
-
-#define BOOST_SP_PAUSE
-
-#endif
+#include <boost/core/yield_primitives.hpp>
 
 namespace boost
 {
 namespace detail
 {
 
-inline void sp_thread_pause()
-{
-    BOOST_SP_PAUSE
-}
+using boost::core::sp_thread_pause;
 
 } // namespace detail
 } // namespace boost
 
-#undef BOOST_SP_PAUSE
-
 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_PAUSE_HPP_INCLUDED
diff --git a/include/boost/smart_ptr/detail/sp_thread_sleep.hpp b/include/boost/smart_ptr/detail/sp_thread_sleep.hpp
index ff1d168..95cee95 100644
--- a/include/boost/smart_ptr/detail/sp_thread_sleep.hpp
+++ b/include/boost/smart_ptr/detail/sp_thread_sleep.hpp
@@ -1,104 +1,20 @@
 #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_SLEEP_HPP_INCLUDED
 #define BOOST_SMART_PTR_DETAIL_SP_THREAD_SLEEP_HPP_INCLUDED
 
-// MS compatible compilers support #pragma once
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1020)
-# pragma once
-#endif
-
-// boost/smart_ptr/detail/sp_thread_sleep.hpp
-//
-// inline void bost::detail::sp_thread_sleep();
-//
-//   Cease execution for a while to yield to other threads,
-//   as if by calling nanosleep() with an appropriate interval.
-//
-// Copyright 2008, 2020 Peter Dimov
-// Distributed under the Boost Software License, Version 1.0
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
-#include <boost/config.hpp>
-#include <boost/config/pragma_message.hpp>
-
-#if defined( WIN32 ) || defined( _WIN32 ) || defined( __WIN32__ ) || defined( __CYGWIN__ )
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using Sleep(1) in sp_thread_sleep")
-#endif
-
-#include <boost/smart_ptr/detail/sp_win32_sleep.hpp>
+#include <boost/core/yield_primitives.hpp>
 
 namespace boost
 {
-
 namespace detail
 {
 
-inline void sp_thread_sleep()
-{
-    Sleep( 1 );
-}
+using boost::core::sp_thread_sleep;
 
 } // namespace detail
-
 } // namespace boost
 
-#elif defined(BOOST_HAS_NANOSLEEP)
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using nanosleep() in sp_thread_sleep")
-#endif
-
-#include <time.h>
-
-namespace boost
-{
-
-namespace detail
-{
-
-inline void sp_thread_sleep()
-{
-    // 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
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using sp_thread_yield() in sp_thread_sleep")
-#endif
-
-#include <boost/smart_ptr/detail/sp_thread_yield.hpp>
-
-namespace boost
-{
-
-namespace detail
-{
-
-inline void sp_thread_sleep()
-{
-    sp_thread_yield();
-}
-
-} // namespace detail
-
-} // namespace boost
-
-#endif
-
 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_SLEEP_HPP_INCLUDED
diff --git a/include/boost/smart_ptr/detail/sp_thread_yield.hpp b/include/boost/smart_ptr/detail/sp_thread_yield.hpp
index 9a221cc..4b79521 100644
--- a/include/boost/smart_ptr/detail/sp_thread_yield.hpp
+++ b/include/boost/smart_ptr/detail/sp_thread_yield.hpp
@@ -1,100 +1,20 @@
 #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_YIELD_HPP_INCLUDED
 #define BOOST_SMART_PTR_DETAIL_SP_THREAD_YIELD_HPP_INCLUDED
 
-// MS compatible compilers support #pragma once
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1020)
-# pragma once
-#endif
-
-// boost/smart_ptr/detail/sp_thread_yield.hpp
-//
-// inline void bost::detail::sp_thread_yield();
-//
-//   Gives up the remainder of the time slice,
-//   as if by calling sched_yield().
-//
-// Copyright 2008, 2020 Peter Dimov
-// Distributed under the Boost Software License, Version 1.0
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
-#include <boost/config.hpp>
-#include <boost/config/pragma_message.hpp>
-
-#if defined( WIN32 ) || defined( _WIN32 ) || defined( __WIN32__ ) || defined( __CYGWIN__ )
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using Sleep(0) in sp_thread_yield")
-#endif
-
-#include <boost/smart_ptr/detail/sp_win32_sleep.hpp>
+#include <boost/core/yield_primitives.hpp>
 
 namespace boost
 {
-
 namespace detail
 {
 
-inline void sp_thread_yield()
-{
-    Sleep( 0 );
-}
+using boost::core::sp_thread_yield;
 
 } // namespace detail
-
 } // namespace boost
 
-#elif defined(BOOST_HAS_SCHED_YIELD)
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using sched_yield() in sp_thread_yield")
-#endif
-
-#ifndef _AIX
-# include <sched.h>
-#else
-  // AIX's sched.h defines ::var which sometimes conflicts with Lambda's var
-  extern "C" int sched_yield(void);
-#endif
-
-namespace boost
-{
-
-namespace detail
-{
-
-inline void sp_thread_yield()
-{
-    sched_yield();
-}
-
-} // namespace detail
-
-} // namespace boost
-
-#else
-
-#if defined(BOOST_SP_REPORT_IMPLEMENTATION)
-  BOOST_PRAGMA_MESSAGE("Using sp_thread_pause() in sp_thread_yield")
-#endif
-
-#include <boost/smart_ptr/detail/sp_thread_pause.hpp>
-
-namespace boost
-{
-
-namespace detail
-{
-
-inline void sp_thread_yield()
-{
-    sp_thread_pause();
-}
-
-} // namespace detail
-
-} // namespace boost
-
-#endif
-
 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_THREAD_YIELD_HPP_INCLUDED
diff --git a/include/boost/smart_ptr/detail/sp_win32_sleep.hpp b/include/boost/smart_ptr/detail/sp_win32_sleep.hpp
deleted file mode 100644
index 139a569..0000000
--- a/include/boost/smart_ptr/detail/sp_win32_sleep.hpp
+++ /dev/null
@@ -1,49 +0,0 @@
-#ifndef BOOST_SMART_PTR_DETAIL_SP_WIN32_SLEEP_HPP_INCLUDED
-#define BOOST_SMART_PTR_DETAIL_SP_WIN32_SLEEP_HPP_INCLUDED
-
-// MS compatible compilers support #pragma once
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1020)
-# pragma once
-#endif
-
-// boost/smart_ptr/detail/sp_win32_sleep.hpp
-//
-// Declares the Win32 Sleep() function.
-//
-// Copyright 2008, 2020 Peter Dimov
-// Distributed under the Boost Software License, Version 1.0
-// https://www.boost.org/LICENSE_1_0.txt
-
-#if defined( BOOST_USE_WINDOWS_H )
-# include <windows.h>
-#endif
-
-namespace boost
-{
-namespace detail
-{
-
-#if !defined( BOOST_USE_WINDOWS_H )
-
-#if defined(__clang__) && defined(__x86_64__)
-// clang x64 warns that __stdcall is ignored
-# define BOOST_SP_STDCALL
-#else
-# define BOOST_SP_STDCALL __stdcall
-#endif
-
-#if defined(__LP64__) // Cygwin 64
-  extern "C" __declspec(dllimport) void BOOST_SP_STDCALL Sleep( unsigned int ms );
-#else
-  extern "C" __declspec(dllimport) void BOOST_SP_STDCALL Sleep( unsigned long ms );
-#endif
-
-#undef BOOST_SP_STDCALL
-
-#endif // !defined( BOOST_USE_WINDOWS_H )
-
-} // namespace detail
-} // namespace boost
-
-#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_WIN32_SLEEP_HPP_INCLUDED