diff options
| author | Conrad Meyer <cem@FreeBSD.org> | 2018-10-22 20:00:30 +0000 |
|---|---|---|
| committer | Conrad Meyer <cem@FreeBSD.org> | 2018-10-22 20:00:30 +0000 |
| commit | 706cfae467a217cc786fd96a72cc2e33c61987e4 (patch) | |
| tree | e7673904660df47b5abd9a1c33cf982a514dac66 /lib/common/compiler.h | |
| parent | 42239e68a5cfba3b37b054425eace8d14e0844e3 (diff) | |
Notes
Diffstat (limited to 'lib/common/compiler.h')
| -rw-r--r-- | lib/common/compiler.h | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/lib/common/compiler.h b/lib/common/compiler.h index e90a3bcde36ce..07f875e4d38e0 100644 --- a/lib/common/compiler.h +++ b/lib/common/compiler.h @@ -77,9 +77,9 @@ * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default. */ #ifndef DYNAMIC_BMI2 - #if (defined(__clang__) && __has_attribute(__target__)) \ + #if ((defined(__clang__) && __has_attribute(__target__)) \ || (defined(__GNUC__) \ - && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) \ + && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \ && (defined(__x86_64__) || defined(_M_X86)) \ && !defined(__BMI2__) # define DYNAMIC_BMI2 1 @@ -88,15 +88,37 @@ #endif #endif -/* prefetch */ -#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */ -# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */ -# define PREFETCH(ptr) _mm_prefetch((const char*)ptr, _MM_HINT_T0) -#elif defined(__GNUC__) -# define PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0) +/* prefetch + * can be disabled, by declaring NO_PREFETCH macro + * All prefetch invocations use a single default locality 2, + * generating instruction prefetcht1, + * which, according to Intel, means "load data into L2 cache". + * This is a good enough "middle ground" for the time being, + * though in theory, it would be better to specialize locality depending on data being prefetched. + * Tests could not determine any sensible difference based on locality value. */ +#if defined(NO_PREFETCH) +# define PREFETCH(ptr) (void)(ptr) /* disabled */ #else -# define PREFETCH(ptr) /* disabled */ -#endif +# if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */ +# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */ +# define PREFETCH(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1) +# elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) +# define PREFETCH(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) +# else +# define PREFETCH(ptr) (void)(ptr) /* disabled */ +# endif +#endif /* NO_PREFETCH */ + +#define CACHELINE_SIZE 64 + +#define PREFETCH_AREA(p, s) { \ + const char* const _ptr = (const char*)(p); \ + size_t const _size = (size_t)(s); \ + size_t _pos; \ + for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ + PREFETCH(_ptr + _pos); \ + } \ +} /* disable warnings */ #ifdef _MSC_VER /* Visual Studio */ |