From 7557eb6adb6b5bec85491f6edd5775201a37a8eb Mon Sep 17 00:00:00 2001 From: Pierre-Marc Fournier Date: Sat, 7 Feb 2009 02:11:22 -0500 Subject: [PATCH] ust: add kernel prefetch.h --- libmarkers/prefetch.h | 64 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 libmarkers/prefetch.h diff --git a/libmarkers/prefetch.h b/libmarkers/prefetch.h new file mode 100644 index 0000000..af7c36a --- /dev/null +++ b/libmarkers/prefetch.h @@ -0,0 +1,64 @@ +/* + * Generic cache management functions. Everything is arch-specific, + * but this header exists to make sure the defines/functions can be + * used in a generic way. + * + * 2000-11-13 Arjan van de Ven + * + */ + +#ifndef _LINUX_PREFETCH_H +#define _LINUX_PREFETCH_H + +#include +#include +#include + +/* + prefetch(x) attempts to pre-emptively get the memory pointed to + by address "x" into the CPU L1 cache. + prefetch(x) should not cause any kind of exception, prefetch(0) is + specifically ok. + + prefetch() should be defined by the architecture, if not, the + #define below provides a no-op define. + + There are 3 prefetch() macros: + + prefetch(x) - prefetches the cacheline at "x" for read + prefetchw(x) - prefetches the cacheline at "x" for write + spin_lock_prefetch(x) - prefetches the spinlock *x for taking + + there is also PREFETCH_STRIDE which is the architecure-prefered + "lookahead" size for prefetching streamed operations. + +*/ + +#ifndef ARCH_HAS_PREFETCH +#define prefetch(x) __builtin_prefetch(x) +#endif + +#ifndef ARCH_HAS_PREFETCHW +#define prefetchw(x) __builtin_prefetch(x,1) +#endif + +#ifndef ARCH_HAS_SPINLOCK_PREFETCH +#define spin_lock_prefetch(x) prefetchw(x) +#endif + +#ifndef PREFETCH_STRIDE +#define PREFETCH_STRIDE (4*L1_CACHE_BYTES) +#endif + +static inline void prefetch_range(void *addr, size_t len) +{ +#ifdef ARCH_HAS_PREFETCH + char *cp; + char *end = addr + len; + + for (cp = addr; cp < end; cp += PREFETCH_STRIDE) + prefetch(cp); +#endif +} + +#endif -- 2.34.1