From 5c74e47cd628a6fcd2e4eba021301e275f8a95a3 Mon Sep 17 00:00:00 2001
From: Ling Ma <ling.ml@alibaba-inc.com>
Date: Thu, 19 Jun 2014 13:00:56 -0700
Subject: [PATCH] Add x86_64 memset optimized for AVX2
In this patch we take advantage of HSW memory bandwidth, manage to
reduce miss branch prediction by avoiding using branch instructions and
force destination to be aligned with avx & avx2 instruction.
The CPU2006 403.gcc benchmark indicates this patch improves performance
from 26% to 59%.
* sysdeps/x86_64/multiarch/Makefile: Add memset-avx2.
* sysdeps/x86_64/multiarch/memset-avx2.S: New file.
* sysdeps/x86_64/multiarch/memset.S: Likewise.
* sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
* sysdeps/x86_64/multiarch/rtld-memset.S: Likewise.
---
ChangeLog | 9 ++
sysdeps/x86_64/multiarch/Makefile | 4 +-
sysdeps/x86_64/multiarch/memset-avx2.S | 168 +++++++++++++++++++++++++++++++++
sysdeps/x86_64/multiarch/memset.S | 59 ++++++++++++
sysdeps/x86_64/multiarch/memset_chk.S | 44 +++++++++
sysdeps/x86_64/multiarch/rtld-memset.S | 1 +
6 files changed, 284 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/x86_64/multiarch/memset-avx2.S
create mode 100644 sysdeps/x86_64/multiarch/memset.S
create mode 100644 sysdeps/x86_64/multiarch/memset_chk.S
create mode 100644 sysdeps/x86_64/multiarch/rtld-memset.S
@@ -1,3 +1,12 @@
+2014-06-19 Ling Ma <ling.ml@alibaba-inc.com>
+ H.J. Lu <hongjiu.lu@intel.com>
+
+ * sysdeps/x86_64/multiarch/Makefile: Add memset-avx2.
+ * sysdeps/x86_64/multiarch/memset-avx2.S: New file.
+ * sysdeps/x86_64/multiarch/memset.S: Likewise.
+ * sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
+ * sysdeps/x86_64/multiarch/rtld-memset.S: Likewise.
+
2014-06-19 Andreas Schwab <schwab@linux-m68k.org>
[BZ #17069]
@@ -17,7 +17,9 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
strcpy-sse2-unaligned strncpy-sse2-unaligned \
stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
strcat-sse2-unaligned strncat-sse2-unaligned \
- strchr-sse2-no-bsf memcmp-ssse3 strstr-sse2-unaligned
+ strchr-sse2-no-bsf memcmp-ssse3 strstr-sse2-unaligned \
+ memset-avx2
+
ifeq (yes,$(config-cflags-sse4))
sysdep_routines += strcspn-c strpbrk-c strspn-c varshift
CFLAGS-varshift.c += -msse4
new file mode 100644
@@ -0,0 +1,168 @@
+/* memset with AVX2
+ Copyright (C) 2014 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 !defined NOT_IN_libc
+
+#include "asm-syntax.h"
+#ifndef MEMSET
+# define MEMSET __memset_avx2
+# define MEMSET_CHK __memset_chk_avx2
+#endif
+
+ .section .text.avx2,"ax",@progbits
+#if defined PIC
+ENTRY (MEMSET_CHK)
+ cmpq %rdx, %rcx
+ jb HIDDEN_JUMPTARGET (__chk_fail)
+END (MEMSET_CHK)
+#endif
+
+ENTRY (MEMSET)
+ 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 $256, %rdx
+ jae L(256bytesormore)
+ cmp $128, %dl
+ jb L(less_128bytes)
+ vmovdqu %xmm0, (%rdi)
+ vmovdqu %xmm0, 0x10(%rdi)
+ vmovdqu %xmm0, 0x20(%rdi)
+ vmovdqu %xmm0, 0x30(%rdi)
+ vmovdqu %xmm0, 0x40(%rdi)
+ vmovdqu %xmm0, 0x50(%rdi)
+ vmovdqu %xmm0, 0x60(%rdi)
+ vmovdqu %xmm0, 0x70(%rdi)
+ vmovdqu %xmm0, -0x80(%rsi)
+ vmovdqu %xmm0, -0x70(%rsi)
+ vmovdqu %xmm0, -0x60(%rsi)
+ vmovdqu %xmm0, -0x50(%rsi)
+ vmovdqu %xmm0, -0x40(%rsi)
+ vmovdqu %xmm0, -0x30(%rsi)
+ vmovdqu %xmm0, -0x20(%rsi)
+ vmovdqu %xmm0, -0x10(%rsi)
+ ret
+
+ .p2align 4
+L(less_128bytes):
+ cmp $64, %dl
+ jb L(less_64bytes)
+ vmovdqu %xmm0, (%rdi)
+ vmovdqu %xmm0, 0x10(%rdi)
+ vmovdqu %xmm0, 0x20(%rdi)
+ vmovdqu %xmm0, 0x30(%rdi)
+ vmovdqu %xmm0, -0x40(%rsi)
+ vmovdqu %xmm0, -0x30(%rsi)
+ vmovdqu %xmm0, -0x20(%rsi)
+ vmovdqu %xmm0, -0x10(%rsi)
+ ret
+
+ .p2align 4
+L(less_64bytes):
+ cmp $32, %dl
+ jb L(less_32bytes)
+ vmovdqu %xmm0, (%rdi)
+ vmovdqu %xmm0, 0x10(%rdi)
+ vmovdqu %xmm0, -0x20(%rsi)
+ vmovdqu %xmm0, -0x10(%rsi)
+ ret
+
+ .p2align 4
+L(less_32bytes):
+ vmovdqu %xmm0, (%rdi)
+ vmovdqu %xmm0, -0x10(%rsi)
+ ret
+
+ .p2align 4
+L(less_16bytes):
+ cmp $8, %dl
+ jb L(less_8bytes)
+ vmovq %xmm0, (%rdi)
+ vmovq %xmm0, -0x08(%rsi)
+ ret
+
+ .p2align 4
+L(less_8bytes):
+ vmovd %xmm0, %ecx
+ cmp $4, %dl
+ jb L(less_4bytes)
+ mov %ecx, (%rdi)
+ mov %ecx, -0x04(%rsi)
+ ret
+
+ .p2align 4
+L(less_4bytes):
+ cmp $2, %dl
+ jb L(less_2bytes)
+ mov %cx, (%rdi)
+ mov %cx, -0x02(%rsi)
+ ret
+
+ .p2align 4
+L(less_2bytes):
+ cmp $1, %dl
+ jb L(less_1bytes)
+ mov %cl, (%rdi)
+L(less_1bytes):
+ ret
+
+ .p2align 4
+L(256bytesormore):
+ vinserti128 $1, %xmm0, %ymm0, %ymm0
+ and $-0x20, %rdi
+ add $0x20, %rdi
+ vmovdqu %ymm0, (%rax)
+ sub %rdi, %rax
+ lea -0x80(%rax, %rdx), %rcx
+ cmp $4096, %rcx
+ ja L(gobble_data)
+L(gobble_128_loop):
+ vmovdqa %ymm0, (%rdi)
+ vmovdqa %ymm0, 0x20(%rdi)
+ vmovdqa %ymm0, 0x40(%rdi)
+ vmovdqa %ymm0, 0x60(%rdi)
+ sub $-0x80, %rdi
+ add $-0x80, %ecx
+ jb L(gobble_128_loop)
+ mov %rsi, %rax
+ vmovdqu %ymm0, -0x80(%rsi)
+ vmovdqu %ymm0, -0x60(%rsi)
+ vmovdqu %ymm0, -0x40(%rsi)
+ vmovdqu %ymm0, -0x20(%rsi)
+ sub %rdx, %rax
+ vzeroupper
+ ret
+
+ .p2align 4
+L(gobble_data):
+ sub $-0x80, %rcx
+ vmovd %xmm0, %eax
+ rep stosb
+ mov %rsi, %rax
+ sub %rdx, %rax
+ vzeroupper
+ ret
+
+END (MEMSET)
+#endif
new file mode 100644
@@ -0,0 +1,59 @@
+/* Multiple versions of memset
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2014 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>
+#include <shlib-compat.h>
+#include <init-arch.h>
+
+/* Define multiple versions only for the definition in lib. */
+#ifndef NOT_IN_libc
+ENTRY(memset)
+ .type memset, @gnu_indirect_function
+ cmpl $0, __cpu_features+KIND_OFFSET(%rip)
+ jne 1f
+ call __init_cpu_features
+1: leaq __memset_sse2(%rip), %rax
+ testl $bit_AVX2_Usable, __cpu_features+FEATURE_OFFSET+index_AVX2_Usable(%rip)
+ jz 2f
+ leaq __memset_avx2(%rip), %rax
+2: ret
+END(memset)
+#endif
+
+#if !defined NOT_IN_libc
+# undef memset
+# define memset __memset_sse2
+
+# undef __memset_chk
+# define __memset_chk __memset_chk_sse2
+
+# ifdef SHARED
+# undef libc_hidden_builtin_def
+/* It doesn't make sense to send libc-internal memset calls through a PLT.
+ The speedup we get from using GPR instruction is likely eaten away
+ by the indirect call in the PLT. */
+# define libc_hidden_builtin_def(name) \
+ .globl __GI_memset; __GI_memset = __memset_sse2
+# endif
+
+# undef strong_alias
+# define strong_alias(original, alias)
+#endif
+
+#include "../memset.S"
new file mode 100644
@@ -0,0 +1,44 @@
+/* Multiple versions of memset_chk
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2014 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>
+#include <init-arch.h>
+
+/* Define multiple versions only for the definition in lib. */
+#ifndef NOT_IN_libc
+# ifdef SHARED
+ENTRY(__memset_chk)
+ .type __memset_chk, @gnu_indirect_function
+ cmpl $0, __cpu_features+KIND_OFFSET(%rip)
+ jne 1f
+ call __init_cpu_features
+1: leaq __memset_chk_sse2(%rip), %rax
+ testl $bit_AVX2_Usable, __cpu_features+FEATURE_OFFSET+index_AVX2_Usable(%rip)
+ jz 2f
+ leaq __memset_chk_avx2(%rip), %rax
+2: ret
+END(__memset_chk)
+
+strong_alias (__memset_chk, __memset_zero_constant_len_parameter)
+ .section .gnu.warning.__memset_zero_constant_len_parameter
+ .string "memset used with constant zero length parameter; this could be due to transposed parameters"
+# else
+# include "../memset_chk.S"
+# endif
+#endif
new file mode 100644
@@ -0,0 +1 @@
+#include "../rtld-memset.S"
--
1.9.3