mirror of
https://github.com/mutouyun/cpp-ipc.git
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95 lines
2.7 KiB
C++
95 lines
2.7 KiB
C++
#pragma once
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#include <cstddef>
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#include <cstdint>
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#include <limits>
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#include <thread>
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namespace ipc {
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// types
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using byte_t = std::uint8_t;
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template <std::size_t N>
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struct uint;
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template <> struct uint<8 > { using type = std::uint8_t ; };
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template <> struct uint<16> { using type = std::uint16_t; };
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template <> struct uint<32> { using type = std::uint32_t; };
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template <std::size_t N>
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using uint_t = typename uint<N>::type;
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// constants
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enum : std::size_t {
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error_count = std::numeric_limits<std::size_t>::max(),
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data_length = 16
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};
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} // namespace ipc
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////////////////////////////////////////////////////////////////
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/// Gives hint to processor that improves performance of spin-wait loops.
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////////////////////////////////////////////////////////////////
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#pragma push_macro("IPC_LOCK_PAUSE_")
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#undef IPC_LOCK_PAUSE_
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#if defined(_MSC_VER)
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#include <windows.h> // YieldProcessor
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/*
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See: http://msdn.microsoft.com/en-us/library/windows/desktop/ms687419(v=vs.85).aspx
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Not for intel c++ compiler, so ignore http://software.intel.com/en-us/forums/topic/296168
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*/
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# define IPC_LOCK_PAUSE_() YieldProcessor()
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#elif defined(__GNUC__)
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#if defined(__i386__) || defined(__x86_64__)
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/*
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See: Intel(R) 64 and IA-32 Architectures Software Developer's Manual V2
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PAUSE-Spin Loop Hint, 4-57
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http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.html?wapkw=instruction+set+reference
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*/
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# define IPC_LOCK_PAUSE_() __asm__ __volatile__("pause")
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#elif defined(__ia64__) || defined(__ia64)
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/*
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See: Intel(R) Itanium(R) Architecture Developer's Manual, Vol.3
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hint - Performance Hint, 3:145
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http://www.intel.com/content/www/us/en/processors/itanium/itanium-architecture-vol-3-manual.html
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*/
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# define IPC_LOCK_PAUSE_() __asm__ __volatile__ ("hint @pause")
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#elif defined(__arm__)
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/*
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See: ARM Architecture Reference Manuals (YIELD)
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http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.subset.architecture.reference/index.html
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*/
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# define IPC_LOCK_PAUSE_() __asm__ __volatile__ ("yield")
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#endif
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#endif/*compilers*/
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#if !defined(IPC_LOCK_PAUSE_)
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/*
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Just use a compiler fence, prevent compiler from optimizing loop
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*/
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# define IPC_LOCK_PAUSE_() std::atomic_signal_fence(std::memory_order_seq_cst)
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#endif/*!defined(IPC_LOCK_PAUSE_)*/
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////////////////////////////////////////////////////////////////
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/// Yield to other threads
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////////////////////////////////////////////////////////////////
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namespace ipc {
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inline void yield(unsigned k) {
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if (k < 4) { /* Do nothing */ }
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else
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if (k < 16) { IPC_LOCK_PAUSE_(); }
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else
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{ std::this_thread::yield(); }
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}
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} // namespace ipc
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#pragma pop_macro("IPC_LOCK_PAUSE_")
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