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[Qemu-devel] [PATCH v3 9/9] cutils: Remove ppc buffer zero checking
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH v3 9/9] cutils: Remove ppc buffer zero checking |
Date: |
Mon, 29 Aug 2016 11:46:20 -0700 |
For ppc64le, gcc6 does extremely poorly with the Altivec code.
Moreover, on POWER7 and POWER8, a hand-optimized Altivec version
turns out to be no faster than the revised integer version, and
therefore not worth the effort.
Signed-off-by: Richard Henderson <address@hidden>
---
util/bufferiszero.c | 55 +----------------------------------------------------
1 file changed, 1 insertion(+), 54 deletions(-)
diff --git a/util/bufferiszero.c b/util/bufferiszero.c
index 6d13d7f..3b39f82 100644
--- a/util/bufferiszero.c
+++ b/util/bufferiszero.c
@@ -29,35 +29,6 @@
/* vector definitions */
-extern void link_error(void);
-
-#define ACCEL_BUFFER_ZERO(NAME, SIZE, VECTYPE, NONZERO) \
-static bool NAME(const void *buf, size_t len) \
-{ \
- const void *end = buf + len; \
- do { \
- const VECTYPE *p = buf; \
- VECTYPE t; \
- __builtin_prefetch(buf + SIZE); \
- barrier(); \
- if (SIZE == sizeof(VECTYPE) * 4) { \
- t = (p[0] | p[1]) | (p[2] | p[3]); \
- } else if (SIZE == sizeof(VECTYPE) * 8) { \
- t = p[0] | p[1]; \
- t |= p[2] | p[3]; \
- t |= p[4] | p[5]; \
- t |= p[6] | p[7]; \
- } else { \
- link_error(); \
- } \
- if (unlikely(NONZERO(t))) { \
- return false; \
- } \
- buf += SIZE; \
- } while (buf < end); \
- return true; \
-}
-
typedef bool (*accel_zero_fn)(const void *, size_t);
static bool
@@ -98,31 +69,7 @@ buffer_zero_int(const void *buf, size_t len)
}
}
-#ifdef __ALTIVEC__
-#include <altivec.h>
-/* The altivec.h header says we're allowed to undef these for
- * C++ compatibility. Here we don't care about C++, but we
- * undef them anyway to avoid namespace pollution.
- * altivec.h may redefine the bool macro as vector type.
- * Reset it to POSIX semantics.
- */
-#undef vector
-#undef pixel
-#undef bool
-#define bool _Bool
-#define DO_NONZERO(X) vec_any_ne(X, (__vector unsigned char){ 0 })
-ACCEL_BUFFER_ZERO(buffer_zero_ppc, 128, __vector unsigned char, DO_NONZERO)
-
-static bool select_accel_fn(const void *buf, size_t len)
-{
- uintptr_t ibuf = (uintptr_t)buf;
- if (len % 128 == 0 && ibuf % sizeof(__vector unsigned char) == 0) {
- return buffer_zero_ppc(buf, len);
- }
- return buffer_zero_int(buf, len);
-}
-
-#elif defined(CONFIG_AVX2_OPT) || defined(__SSE2__)
+#if defined(CONFIG_AVX2_OPT) || defined(__SSE2__)
#include <cpuid.h>
#include <x86intrin.h>
--
2.7.4
- [Qemu-devel] [PATCH v3 0/9] Improve buffer_is_zero, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 3/9] cutils: Export only buffer_is_zero, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 1/9] cutils: Move buffer_is_zero and subroutines to a new file, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 4/9] cutils: Rearrange buffer_is_zero acceleration, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 9/9] cutils: Remove ppc buffer zero checking,
Richard Henderson <=
- [Qemu-devel] [PATCH v3 8/9] cutils: Remove aarch64 buffer zero checking, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 6/9] cutils: Add generic prefetch, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 5/9] cutils: Add test for buffer_is_zero, Richard Henderson, 2016/08/29
- [Qemu-devel] [PATCH v3 7/9] cutils: Rewrite x86 buffer zero checking, Richard Henderson, 2016/08/29
- Re: [Qemu-devel] [PATCH v3 0/9] Improve buffer_is_zero, Paolo Bonzini, 2016/08/30