prefix.h

Go to the documentation of this file.

 
#ifndef QB_UTILS_PREFIX_H
#define QB_UTILS_PREFIX_H
 
/* this file defines the following macros:
   QB_LOCKFREE_CACHELINE_BYTES: size of a cache line
   QB_LOCKFREE_EVENT_BUCKET_BYTES: size of a event partition
   QB_LOCKFREE_PTR_COMPRESSION: use tag/pointer compression to utilize parts
                                   of the virtual address space as tag (at least 16bit)
   QB_LOCKFREE_DCAS_ALIGNMENT:  symbol used for aligning structs at cache line
                                   boundaries
*/

constexpr std::size_t
cache_line_size() {
#ifdef KNOWN_L1_CACHE_LINE_SIZE
    return KNOWN_L1_CACHE_LINE_SIZE;
#elif defined(__cpp_lib_hardware_interference_size)
    return std::hardware_destructive_interference_size;
#else
    return 64;
#endif
}
 
#define QB_LOCKFREE_CACHELINE_BYTES cache_line_size()
#define QB_LOCKFREE_EVENT_BUCKET_BYTES cache_line_size()
 
#ifdef _MSC_VER
 
#define QB_LOCKFREE_CACHELINE_ALIGNMENT __declspec(align(QB_LOCKFREE_CACHELINE_BYTES))
#define QB_LOCKFREE_EVENT_BUCKET_ALIGNMENT \
    __declspec(align(QB_LOCKFREE_EVENT_BUCKET_BYTES))
 
#if defined(_M_IX86)
#define QB_LOCKFREE_DCAS_ALIGNMENT
#elif defined(_M_X64) || defined(_M_IA64)
#define QB_LOCKFREE_PTR_COMPRESSION 1
#define QB_LOCKFREE_DCAS_ALIGNMENT __declspec(align(16))
#endif
 
#endif /* _MSC_VER */
 
#ifdef __GNUC__
 
#define QB_LOCKFREE_CACHELINE_ALIGNMENT alignas(QB_LOCKFREE_CACHELINE_BYTES)
#define QB_LOCKFREE_EVENT_BUCKET_ALIGNMENT alignas(QB_LOCKFREE_EVENT_BUCKET_BYTES)
 
#if defined(__i386__) || defined(__ppc__)
#define QB_LOCKFREE_DCAS_ALIGNMENT
#elif defined(__x86_64__)
#define QB_LOCKFREE_PTR_COMPRESSION 1
#define QB_LOCKFREE_DCAS_ALIGNMENT __attribute__((aligned(16)))
#elif defined(__alpha__)
#define QB_LOCKFREE_PTR_COMPRESSION 1
#define QB_LOCKFREE_DCAS_ALIGNMENT
#endif
#endif /* __GNUC__ */

struct QB_LOCKFREE_CACHELINE_ALIGNMENT CacheLine {
    uint32_t __raw__[QB_LOCKFREE_CACHELINE_BYTES / sizeof(uint32_t)];
};

struct QB_LOCKFREE_EVENT_BUCKET_ALIGNMENT EventBucket {
    uint32_t __raw__[QB_LOCKFREE_EVENT_BUCKET_BYTES / sizeof(uint32_t)];
};
 
#endif /* QB_UTILS_PREFIX_H */