[PATCH 3/4] x86/xor: add alternative SSE implementation onlyprefetching once per 64-byte line
From: Jan Beulich
Date: Mon Sep 10 2012 - 08:39:19 EST
On CPUs with 64-byte last level cache lines, the yields roughly 10%
better performance, independent of CPU vendor or specific model (as far
as I was able to test).
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
arch/x86/include/asm/xor.h | 176 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/xor_32.h | 23 ++---
arch/x86/include/asm/xor_64.h | 10 --
3 files changed, 191 insertions(+), 18 deletions(-)
--- 3.6-rc5-x86-xor.orig/arch/x86/include/asm/xor.h
+++ 3.6-rc5-x86-xor/arch/x86/include/asm/xor.h
@@ -107,6 +107,14 @@ do { \
#define XO2(x, y) " xorps "OFFS(x)"(%[p3]), %%xmm"#y" ;\n"
#define XO3(x, y) " xorps "OFFS(x)"(%[p4]), %%xmm"#y" ;\n"
#define XO4(x, y) " xorps "OFFS(x)"(%[p5]), %%xmm"#y" ;\n"
+#define NOP(x)
+
+#define BLK64(pf, op, i) \
+ pf(i) \
+ op(i, 0) \
+ op(i + 1, 1) \
+ op(i + 2, 2) \
+ op(i + 3, 3)
static void XOR_ALIGN_STACK
xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
@@ -161,6 +169,41 @@ xor_sse_2(unsigned long bytes, unsigned
}
static void XOR_ALIGN_STACK
+xor_sse_2_pf64(unsigned long bytes, unsigned long *p1, unsigned long *p2)
+{
+ unsigned long cr0, lines = bytes >> 8;
+ char xmm_save[16*4] __aligned(XOR_ALIGN);
+
+ XMMS_SAVE;
+
+ asm volatile(
+#undef BLOCK
+#define BLOCK(i) \
+ BLK64(PF0, LD, i) \
+ BLK64(PF1, XO1, i) \
+ BLK64(NOP, ST, i) \
+
+ " .align 32 ;\n"
+ " 1: ;\n"
+
+ BLOCK(0)
+ BLOCK(4)
+ BLOCK(8)
+ BLOCK(12)
+
+ " add %[inc], %[p1] ;\n"
+ " add %[inc], %[p2] ;\n"
+ " dec %[cnt] ;\n"
+ " jnz 1b ;\n"
+ : [cnt] "+r" (lines),
+ [p1] "+r" (p1), [p2] "+r" (p2)
+ : [inc] XOR_CONSTANT_CONSTRAINT (256UL)
+ : "memory");
+
+ XMMS_RESTORE;
+}
+
+static void XOR_ALIGN_STACK
xor_sse_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3)
{
@@ -221,6 +264,44 @@ xor_sse_3(unsigned long bytes, unsigned
}
static void XOR_ALIGN_STACK
+xor_sse_3_pf64(unsigned long bytes, unsigned long *p1, unsigned long *p2,
+ unsigned long *p3)
+{
+ unsigned long cr0, lines = bytes >> 8;
+ char xmm_save[16*4] __aligned(XOR_ALIGN);
+
+ XMMS_SAVE;
+
+ asm volatile(
+#undef BLOCK
+#define BLOCK(i) \
+ BLK64(PF0, LD, i) \
+ BLK64(PF1, XO1, i) \
+ BLK64(PF2, XO2, i) \
+ BLK64(NOP, ST, i) \
+
+ " .align 32 ;\n"
+ " 1: ;\n"
+
+ BLOCK(0)
+ BLOCK(4)
+ BLOCK(8)
+ BLOCK(12)
+
+ " add %[inc], %[p1] ;\n"
+ " add %[inc], %[p2] ;\n"
+ " add %[inc], %[p3] ;\n"
+ " dec %[cnt] ;\n"
+ " jnz 1b ;\n"
+ : [cnt] "+r" (lines),
+ [p1] "+r" (p1), [p2] "+r" (p2), [p3] "+r" (p3)
+ : [inc] XOR_CONSTANT_CONSTRAINT (256UL)
+ : "memory");
+
+ XMMS_RESTORE;
+}
+
+static void XOR_ALIGN_STACK
xor_sse_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4)
{
@@ -288,6 +369,46 @@ xor_sse_4(unsigned long bytes, unsigned
}
static void XOR_ALIGN_STACK
+xor_sse_4_pf64(unsigned long bytes, unsigned long *p1, unsigned long *p2,
+ unsigned long *p3, unsigned long *p4)
+{
+ unsigned long cr0, lines = bytes >> 8;
+ char xmm_save[16*4] __aligned(XOR_ALIGN);
+
+ XMMS_SAVE;
+
+ asm volatile(
+#undef BLOCK
+#define BLOCK(i) \
+ BLK64(PF0, LD, i) \
+ BLK64(PF1, XO1, i) \
+ BLK64(PF2, XO2, i) \
+ BLK64(PF3, XO3, i) \
+ BLK64(NOP, ST, i) \
+
+ " .align 32 ;\n"
+ " 1: ;\n"
+
+ BLOCK(0)
+ BLOCK(4)
+ BLOCK(8)
+ BLOCK(12)
+
+ " add %[inc], %[p1] ;\n"
+ " add %[inc], %[p2] ;\n"
+ " add %[inc], %[p3] ;\n"
+ " add %[inc], %[p4] ;\n"
+ " dec %[cnt] ;\n"
+ " jnz 1b ;\n"
+ : [cnt] "+r" (lines), [p1] "+r" (p1),
+ [p2] "+r" (p2), [p3] "+r" (p3), [p4] "+r" (p4)
+ : [inc] XOR_CONSTANT_CONSTRAINT (256UL)
+ : "memory");
+
+ XMMS_RESTORE;
+}
+
+static void XOR_ALIGN_STACK
xor_sse_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4, unsigned long *p5)
{
@@ -361,12 +482,64 @@ xor_sse_5(unsigned long bytes, unsigned
XMMS_RESTORE;
}
+static void XOR_ALIGN_STACK
+xor_sse_5_pf64(unsigned long bytes, unsigned long *p1, unsigned long *p2,
+ unsigned long *p3, unsigned long *p4, unsigned long *p5)
+{
+ unsigned long cr0, lines = bytes >> 8;
+ char xmm_save[16*4] __aligned(XOR_ALIGN);
+
+ XMMS_SAVE;
+
+ asm volatile(
+#undef BLOCK
+#define BLOCK(i) \
+ BLK64(PF0, LD, i) \
+ BLK64(PF1, XO1, i) \
+ BLK64(PF2, XO2, i) \
+ BLK64(PF3, XO3, i) \
+ BLK64(PF4, XO4, i) \
+ BLK64(NOP, ST, i) \
+
+ " .align 32 ;\n"
+ " 1: ;\n"
+
+ BLOCK(0)
+ BLOCK(4)
+ BLOCK(8)
+ BLOCK(12)
+
+ " add %[inc], %[p1] ;\n"
+ " add %[inc], %[p2] ;\n"
+ " add %[inc], %[p3] ;\n"
+ " add %[inc], %[p4] ;\n"
+ " add %[inc], %[p5] ;\n"
+ " dec %[cnt] ;\n"
+ " jnz 1b ;\n"
+ : [cnt] "+r" (lines), [p1] "+r" (p1), [p2] "+r" (p2),
+ [p3] "+r" (p3), [p4] "+r" (p4), [p5] "+r" (p5)
+ : [inc] XOR_CONSTANT_CONSTRAINT (256UL)
+ : "memory");
+
+ XMMS_RESTORE;
+}
+
+static struct xor_block_template xor_block_sse_pf64 = {
+ .name = "prefetch64-sse",
+ .do_2 = xor_sse_2_pf64,
+ .do_3 = xor_sse_3_pf64,
+ .do_4 = xor_sse_4_pf64,
+ .do_5 = xor_sse_5_pf64,
+};
+
#undef LD
#undef XO1
#undef XO2
#undef XO3
#undef XO4
#undef ST
+#undef NOP
+#undef BLK64
#undef BLOCK
#undef XOR_ALIGN_STACK
@@ -380,4 +553,7 @@ xor_sse_5(unsigned long bytes, unsigned
# include "xor_64.h"
#endif
+#define XOR_SELECT_TEMPLATE(FASTEST) \
+ AVX_SELECT(FASTEST)
+
#endif /* _ASM_X86_XOR_H */
--- 3.6-rc5-x86-xor.orig/arch/x86/include/asm/xor_32.h
+++ 3.6-rc5-x86-xor/arch/x86/include/asm/xor_32.h
@@ -543,26 +543,25 @@ static struct xor_block_template xor_blo
/* Also try the generic routines. */
#include <asm-generic/xor.h>
+/* We force the use of the SSE xor block because it can write around L2.
+ We may also be able to load into the L1 only depending on how the cpu
+ deals with a load to a line that is being prefetched. */
#undef XOR_TRY_TEMPLATES
#define XOR_TRY_TEMPLATES \
do { \
- xor_speed(&xor_block_8regs); \
- xor_speed(&xor_block_8regs_p); \
- xor_speed(&xor_block_32regs); \
- xor_speed(&xor_block_32regs_p); \
AVX_XOR_SPEED; \
- if (cpu_has_xmm) \
+ if (cpu_has_xmm) { \
xor_speed(&xor_block_pIII_sse); \
- if (cpu_has_mmx) { \
+ xor_speed(&xor_block_sse_pf64); \
+ } else if (cpu_has_mmx) { \
xor_speed(&xor_block_pII_mmx); \
xor_speed(&xor_block_p5_mmx); \
+ } else { \
+ xor_speed(&xor_block_8regs); \
+ xor_speed(&xor_block_8regs_p); \
+ xor_speed(&xor_block_32regs); \
+ xor_speed(&xor_block_32regs_p); \
} \
} while (0)
-/* We force the use of the SSE xor block because it can write around L2.
- We may also be able to load into the L1 only depending on how the cpu
- deals with a load to a line that is being prefetched. */
-#define XOR_SELECT_TEMPLATE(FASTEST) \
- AVX_SELECT(cpu_has_xmm ? &xor_block_pIII_sse : FASTEST)
-
#endif /* _ASM_X86_XOR_32_H */
--- 3.6-rc5-x86-xor.orig/arch/x86/include/asm/xor_64.h
+++ 3.6-rc5-x86-xor/arch/x86/include/asm/xor_64.h
@@ -13,17 +13,15 @@ static struct xor_block_template xor_blo
/* Also try the AVX routines */
#include "xor_avx.h"
+/* We force the use of the SSE xor block because it can write around L2.
+ We may also be able to load into the L1 only depending on how the cpu
+ deals with a load to a line that is being prefetched. */
#undef XOR_TRY_TEMPLATES
#define XOR_TRY_TEMPLATES \
do { \
AVX_XOR_SPEED; \
+ xor_speed(&xor_block_sse_pf64); \
xor_speed(&xor_block_sse); \
} while (0)
-/* We force the use of the SSE xor block because it can write around L2.
- We may also be able to load into the L1 only depending on how the cpu
- deals with a load to a line that is being prefetched. */
-#define XOR_SELECT_TEMPLATE(FASTEST) \
- AVX_SELECT(&xor_block_sse)
-
#endif /* _ASM_X86_XOR_64_H */
--
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