Faster memcpy on x64.
We add new memcpy version that uses unaligned loads which are fast on modern processors. This allows second improvement which is avoiding computed jump which is relatively expensive operation. Tests available here: http://kam.mff.cuni.cz/~ondra/memcpy_profile_result27_04_13.tar.bz2
This commit is contained in:
Ondrej Bilka
parent
3e69426875
commit
2d48b41c8f
10
ChangeLog
10
ChangeLog
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@ -1,3 +1,13 @@
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2013-05-20 Ondřej Bílka <neleai@seznam.cz>
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* sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: New file.
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* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Add
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__memcpy_sse2_unaligned ifunc selection.
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* sysdeps/x86_64/multiarch/Makefile (sysdep_routines):
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Add memcpy-sse2-unaligned.S.
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* sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list):
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Add: __memcpy_sse2_unaligned.
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2013-05-19 Joseph Myers <joseph@codesourcery.com>
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[BZ #15490]
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@ -7,7 +7,7 @@ endif
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ifeq ($(subdir),string)
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sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3 \
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strend-sse4 memcmp-sse4 memcpy-ssse3 mempcpy-ssse3 \
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strend-sse4 memcmp-sse4 memcpy-ssse3 memcpy-sse2-unaligned mempcpy-ssse3 \
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memmove-ssse3 memcpy-ssse3-back mempcpy-ssse3-back \
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memmove-ssse3-back strcasestr-nonascii strcasecmp_l-ssse3 \
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strncase_l-ssse3 strcat-ssse3 strncat-ssse3\
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@ -227,6 +227,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
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IFUNC_IMPL_ADD (array, i, memcpy, HAS_SSSE3,
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__memcpy_ssse3_back)
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IFUNC_IMPL_ADD (array, i, memcpy, HAS_SSSE3, __memcpy_ssse3)
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IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_sse2_unaligned)
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IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_sse2))
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/* Support sysdeps/x86_64/multiarch/mempcpy_chk.S. */
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@ -0,0 +1,175 @@
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/* memcpy with unaliged loads
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Copyright (C) 2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include "asm-syntax.h"
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#ifndef ALIGN
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# define ALIGN(n) .p2align n
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#endif
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ENTRY(__memcpy_sse2_unaligned)
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movq %rsi, %rax
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leaq (%rdx,%rdx), %rcx
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subq %rdi, %rax
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subq %rdx, %rax
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cmpq %rcx, %rax
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jb L(overlapping)
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cmpq $16, %rdx
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jbe L(less_16)
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movdqu (%rsi), %xmm8
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cmpq $32, %rdx
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movdqu %xmm8, (%rdi)
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movdqu -16(%rsi,%rdx), %xmm8
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movdqu %xmm8, -16(%rdi,%rdx)
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ja .L31
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L(return):
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movq %rdi, %rax
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ret
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.p2align 4,,10
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ALIGN(4)
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.L31:
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movdqu 16(%rsi), %xmm8
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cmpq $64, %rdx
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movdqu %xmm8, 16(%rdi)
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movdqu -32(%rsi,%rdx), %xmm8
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movdqu %xmm8, -32(%rdi,%rdx)
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jbe L(return)
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movdqu 32(%rsi), %xmm8
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cmpq $128, %rdx
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movdqu %xmm8, 32(%rdi)
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movdqu -48(%rsi,%rdx), %xmm8
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movdqu %xmm8, -48(%rdi,%rdx)
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movdqu 48(%rsi), %xmm8
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movdqu %xmm8, 48(%rdi)
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movdqu -64(%rsi,%rdx), %xmm8
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movdqu %xmm8, -64(%rdi,%rdx)
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jbe L(return)
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leaq 64(%rdi), %rcx
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addq %rdi, %rdx
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andq $-64, %rdx
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andq $-64, %rcx
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movq %rcx, %rax
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subq %rdi, %rax
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addq %rax, %rsi
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cmpq %rdx, %rcx
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je L(return)
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movq %rsi, %r10
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subq %rcx, %r10
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leaq 16(%r10), %r9
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leaq 32(%r10), %r8
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leaq 48(%r10), %rax
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.p2align 4,,10
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ALIGN(4)
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L(loop):
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movdqu (%rcx,%r10), %xmm8
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movdqa %xmm8, (%rcx)
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movdqu (%rcx,%r9), %xmm8
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movdqa %xmm8, 16(%rcx)
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movdqu (%rcx,%r8), %xmm8
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movdqa %xmm8, 32(%rcx)
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movdqu (%rcx,%rax), %xmm8
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movdqa %xmm8, 48(%rcx)
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addq $64, %rcx
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cmpq %rcx, %rdx
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jne L(loop)
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jmp L(return)
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L(overlapping):
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cmpq %rsi, %rdi
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jae .L3
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testq %rdx, %rdx
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.p2align 4,,5
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je L(return)
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movq %rdx, %r9
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leaq 16(%rsi), %rcx
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leaq 16(%rdi), %r8
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shrq $4, %r9
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movq %r9, %rax
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salq $4, %rax
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cmpq %rcx, %rdi
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setae %cl
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cmpq %r8, %rsi
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setae %r8b
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orl %r8d, %ecx
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cmpq $15, %rdx
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seta %r8b
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testb %r8b, %cl
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je .L16
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testq %rax, %rax
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je .L16
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xorl %ecx, %ecx
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xorl %r8d, %r8d
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.L7:
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movdqu (%rsi,%rcx), %xmm8
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addq $1, %r8
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movdqu %xmm8, (%rdi,%rcx)
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addq $16, %rcx
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cmpq %r8, %r9
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ja .L7
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cmpq %rax, %rdx
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je L(return)
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.L21:
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movzbl (%rsi,%rax), %ecx
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movb %cl, (%rdi,%rax)
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addq $1, %rax
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cmpq %rax, %rdx
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ja .L21
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jmp L(return)
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L(less_16):
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testb $24, %dl
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jne L(between_9_16)
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testb $4, %dl
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.p2align 4,,5
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jne L(between_5_8)
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testq %rdx, %rdx
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.p2align 4,,2
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je L(return)
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movzbl (%rsi), %eax
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testb $2, %dl
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movb %al, (%rdi)
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je L(return)
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movzwl -2(%rsi,%rdx), %eax
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movw %ax, -2(%rdi,%rdx)
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jmp L(return)
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.L3:
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leaq -1(%rdx), %rax
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.p2align 4,,10
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ALIGN(4)
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.L11:
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movzbl (%rsi,%rax), %edx
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movb %dl, (%rdi,%rax)
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subq $1, %rax
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jmp .L11
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L(between_9_16):
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movq (%rsi), %rax
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movq %rax, (%rdi)
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movq -8(%rsi,%rdx), %rax
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movq %rax, -8(%rdi,%rdx)
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jmp L(return)
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.L16:
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xorl %eax, %eax
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jmp .L21
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L(between_5_8):
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movl (%rsi), %eax
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movl %eax, (%rdi)
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movl -4(%rsi,%rdx), %eax
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movl %eax, -4(%rdi,%rdx)
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jmp L(return)
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END(__memcpy_sse2_unaligned)
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@ -33,13 +33,14 @@ ENTRY(__new_memcpy)
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jne 1f
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call __init_cpu_features
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1: leaq __memcpy_sse2(%rip), %rax
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testl $bit_SSSE3, __cpu_features+CPUID_OFFSET+index_SSSE3(%rip)
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jz 2f
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leaq __memcpy_ssse3(%rip), %rax
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testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
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jz 2f
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leaq __memcpy_ssse3_back(%rip), %rax
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2: ret
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testl $bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip)
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jnz 2f
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leaq __memcpy_sse2_unaligned(%rip), %rax
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ret
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2: testl $bit_SSSE3, __cpu_features+CPUID_OFFSET+index_SSSE3(%rip)
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jz 3f
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leaq __memcpy_ssse3(%rip), %rax
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3: ret
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END(__new_memcpy)
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# undef ENTRY
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