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Hi,
here is AVX512 memset implementation.
It is faster enough than AVX2 memset on KNL hardware, performance
results attached.
2015-12-03 Andrew Senkevich <andrew.senkevich@intel.com>
* sysdeps/x86_64/multiarch/Makefile: Added new file.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c: Added test.
* sysdeps/x86_64/multiarch/memset-avx512.S: New file.
* sysdeps/x86_64/multiarch/memset.S: Added new IFUNC branch.
* sysdeps/x86_64/multiarch/memset-avx2.S: Added libc_hidden_def for
__memset_avx2.
diff --git a/sysdeps/x86_64/multiarch/Makefile
b/sysdeps/x86_64/multiarch/Makefile
index bb811c2..5bb859e 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -18,7 +18,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c
strcmp-ssse3 \
stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
strcat-sse2-unaligned strncat-sse2-unaligned \
strchr-sse2-no-bsf memcmp-ssse3 strstr-sse2-unaligned \
- strcspn-c strpbrk-c strspn-c varshift memset-avx2
+ strcspn-c strpbrk-c strspn-c varshift memset-avx2
memset-avx512
CFLAGS-varshift.c += -msse4
CFLAGS-strcspn-c.c += -msse4
CFLAGS-strpbrk-c.c += -msse4
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 5c0c219..a8be3eb 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -83,7 +83,10 @@ __libc_ifunc_impl_list (const char *name, struct
libc_ifunc_impl *array,
IFUNC_IMPL_ADD (array, i, memset, 1, __memset_sse2)
IFUNC_IMPL_ADD (array, i, memset,
HAS_ARCH_FEATURE (AVX2_Usable),
- __memset_avx2))
+ __memset_avx2)
+ IFUNC_IMPL_ADD (array, i, memset,
+ HAS_ARCH_FEATURE (AVX512F_Usable),
+ __memset_avx512))
/* Support sysdeps/x86_64/multiarch/stpncpy.S. */
IFUNC_IMPL (i, name, stpncpy,
diff --git a/sysdeps/x86_64/multiarch/memset-avx2.S
b/sysdeps/x86_64/multiarch/memset-avx2.S
index 28eabad..f96baf3 100644
--- a/sysdeps/x86_64/multiarch/memset-avx2.S
+++ b/sysdeps/x86_64/multiarch/memset-avx2.S
@@ -165,4 +165,6 @@ L(gobble_data):
ret
END (MEMSET)
+libc_hidden_def (__memset_avx2)
+
#endif
diff --git a/sysdeps/x86_64/multiarch/memset-avx512.S
b/sysdeps/x86_64/multiarch/memset-avx512.S
new file mode 100644
index 0000000..083177e
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memset-avx512.S
@@ -0,0 +1,191 @@
+/* memset optimized with AVX512.
+ Copyright (C) 2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#if IS_IN (libc)
+
+#include "asm-syntax.h"
+#ifndef MEMSET
+# define MEMSET __memset_avx512
+#endif
+
+ .section .text,"ax",@progbits
+ENTRY (MEMSET)
+#ifdef HAVE_AVX512_ASM_SUPPORT
+ vpxor %xmm0, %xmm0, %xmm0
+ vmovd %esi, %xmm1
+ lea (%rdi, %rdx), %rsi
+ mov %rdi, %rax
+ vpshufb %xmm0, %xmm1, %xmm0
+ cmp $16, %rdx
+ jb L(less_16bytes)
+ cmp $512, %rdx
+ vbroadcastss %xmm0, %zmm2
+ ja L(512bytesormore)
+ cmp $256, %rdx
+ jb L(less_256bytes)
+ vmovups %zmm2, (%rdi)
+ vmovups %zmm2, 0x40(%rdi)
+ vmovups %zmm2, 0x80(%rdi)
+ vmovups %zmm2, 0xC0(%rdi)
+ vmovups %zmm2, -0x100(%rsi)
+ vmovups %zmm2, -0xC0(%rsi)
+ vmovups %zmm2, -0x80(%rsi)
+ vmovups %zmm2, -0x40(%rsi)
+ ret
+
+L(less_256bytes):
+ cmp $128, %dl
+ jb L(less_128bytes)
+ vmovups %zmm2, (%rdi)
+ vmovups %zmm2, 0x40(%rdi)
+ vmovups %zmm2, -0x80(%rsi)
+ vmovups %zmm2, -0x40(%rsi)
+ ret
+
+L(less_128bytes):
+ cmp $64, %dl
+ jb L(less_64bytes)
+ vmovups %zmm2, (%rdi)
+ vmovups %zmm2, -0x40(%rsi)
+ ret
+
+L(less_64bytes):
+ cmp $32, %dl
+ jb L(less_32bytes)
+ vmovdqu %ymm2, (%rdi)
+ vmovdqu %ymm2, -0x20(%rsi)
+ ret
+
+L(less_32bytes):
+ vmovdqu %xmm0, (%rdi)
+ vmovdqu %xmm0, -0x10(%rsi)
+ ret
+
+L(less_16bytes):
+ cmp $8, %dl
+ jb L(less_8bytes)
+ vmovq %xmm0, (%rdi)
+ vmovq %xmm0, -0x08(%rsi)
+ ret
+
+L(less_8bytes):
+ vmovd %xmm0, %ecx
+ cmp $4, %dl
+ jb L(less_4bytes)
+ mov %ecx, (%rdi)
+ mov %ecx, -0x04(%rsi)
+ ret
+
+L(less_4bytes):
+ cmp $2, %dl
+ jb L(less_2bytes)
+ mov %cx, (%rdi)
+ mov %cx, -0x02(%rsi)
+ ret
+
+L(less_2bytes):
+ cmp $1, %dl
+ jb L(less_1bytes)
+ mov %cl, (%rdi)
+L(less_1bytes):
+ ret
+
+L(512bytesormore):
+ mov __x86_shared_cache_size_half(%rip), %rcx
+ cmp %rcx, %rdx
+ ja L(preloop_large)
+ cmp $1024, %rdx
+ ja L(1024bytesormore)
+
+ vmovups %zmm2, (%rdi)
+ vmovups %zmm2, 0x40(%rdi)
+ vmovups %zmm2, 0x80(%rdi)
+ vmovups %zmm2, 0xC0(%rdi)
+ vmovups %zmm2, 0x100(%rdi)
+ vmovups %zmm2, 0x140(%rdi)
+ vmovups %zmm2, 0x180(%rdi)
+ vmovups %zmm2, 0x1C0(%rdi)
+ vmovups %zmm2, -0x200(%rsi)
+ vmovups %zmm2, -0x1C0(%rsi)
+ vmovups %zmm2, -0x180(%rsi)
+ vmovups %zmm2, -0x140(%rsi)
+ vmovups %zmm2, -0x100(%rsi)
+ vmovups %zmm2, -0xC0(%rsi)
+ vmovups %zmm2, -0x80(%rsi)
+ vmovups %zmm2, -0x40(%rsi)
+ ret
+
+/* Align on 64 and loop with aligned stores. */
+L(1024bytesormore):
+ sub $0x100, %rsi
+ vmovups %zmm2, (%rax)
+ and $-0x40, %rdi
+ add $0x40, %rdi
+
+L(gobble_256bytes_loop):
+ vmovaps %zmm2, (%rdi)
+ vmovaps %zmm2, 0x40(%rdi)
+ vmovaps %zmm2, 0x80(%rdi)
+ vmovaps %zmm2, 0xC0(%rdi)
+ add $0x100, %rdi
+ cmp %rsi, %rdi
+ jb L(gobble_256bytes_loop)
+ vmovups %zmm2, (%rsi)
+ vmovups %zmm2, 0x40(%rsi)
+ vmovups %zmm2, 0x80(%rsi)
+ vmovups %zmm2, 0xC0(%rsi)
+ ret
+
+/* Align on 128 and loop with non-temporal stores. */
+L(preloop_large):
+ and $-0x80, %rdi
+ add $0x80, %rdi
+ vmovups %zmm2, (%rax)
+ vmovups %zmm2, 0x40(%rax)
+ sub $0x200, %rsi
+
+L(gobble_512bytes_nt_loop):
+ vmovntdq %zmm2, (%rdi)
+ vmovntdq %zmm2, 0x40(%rdi)
+ vmovntdq %zmm2, 0x80(%rdi)
+ vmovntdq %zmm2, 0xC0(%rdi)
+ vmovntdq %zmm2, 0x100(%rdi)
+ vmovntdq %zmm2, 0x140(%rdi)
+ vmovntdq %zmm2, 0x180(%rdi)
+ vmovntdq %zmm2, 0x1C0(%rdi)
+ add $0x200, %rdi
+ cmp %rsi, %rdi
+ jb L(gobble_512bytes_nt_loop)
+ sfence
+ vmovups %zmm2, (%rsi)
+ vmovups %zmm2, 0x40(%rsi)
+ vmovups %zmm2, 0x80(%rsi)
+ vmovups %zmm2, 0xC0(%rsi)
+ vmovups %zmm2, 0x100(%rsi)
+ vmovups %zmm2, 0x140(%rsi)
+ vmovups %zmm2, 0x180(%rsi)
+ vmovups %zmm2, 0x1C0(%rsi)
+ ret
+#else
+ call HIDDEN_JUMPTARGET(__memset_avx2)
+ ret
+#endif
+END (MEMSET)
+#endif
diff --git a/sysdeps/x86_64/multiarch/memset.S
b/sysdeps/x86_64/multiarch/memset.S
index dbc00d2..0c8c176 100644
--- a/sysdeps/x86_64/multiarch/memset.S
+++ b/sysdeps/x86_64/multiarch/memset.S
@@ -30,6 +30,11 @@ ENTRY(memset)
HAS_ARCH_FEATURE (AVX2_Usable)
jz 2f
leaq __memset_avx2(%rip), %rax
+#ifdef HAVE_AVX512_ASM_SUPPORT
+ HAS_ARCH_FEATURE (AVX512F_Usable)
+ jz 2f
+ leaq __memset_avx512(%rip), %rax
+#endif
2: ret
END(memset)
#endif
--
WBR,
Andrew
Attachment:
memset_avx512_results.tar.bz2
Description: BZip2 compressed data
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