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Re: [PING][PATCH][BZ #12100] strstr with unaligned loads.
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: libc-alpha at sourceware dot org
- Date: Mon, 7 Oct 2013 15:14:30 +0200
- Subject: Re: [PING][PATCH][BZ #12100] strstr with unaligned loads.
- Authentication-results: sourceware.org; auth=none
- References: <20130825090758 dot GA23686 at domone dot kolej dot mff dot cuni dot cz> <20130908204231 dot GA30260 at domone dot kolej dot mff dot cuni dot cz>
ping,
Benchmark results with haswell are available here:
http://kam.mff.cuni.cz/~ondra/benchmark_string/strstr_profile.html
On Sun, Sep 08, 2013 at 10:42:31PM +0200, OndÅej BÃlka wrote:
> ping
> On Sun, Aug 25, 2013 at 11:07:58AM +0200, OndÅej BÃlka wrote:
> > Hi,
> >
> > This patch continues to remove ineffective sse4.2 functions. Now we
> > focus on strstr.
> >
> > I use a techique of doing vectorized search for first pair of characters
> > which is fastest in practice.
> >
> > I analyzed a pcpistri instruction and there is a weakness that degrades
> > performance. In comparison with pcpistri a limiting factor is 16-th
> > character. It gets matched when it corresponds to first character in
> > needle and this leads to many false positives.
> >
> > This weakness could theoreticaly be addressed by using pcpistrm to
> > compute masks at 8 byte intervals and doing bitwise and to ensure that
> > we always check at least 8 bytes.
> >
> > However this does not work in practice because pcpistrm is slow and we
> > are left with pcpistri whose result is mostly useless.
> >
> > New sse2 version is 280% faster on nehalem and fx10 and 400% faster on
> > ivy bridge for random strings where you pick randomly between 16
> > characters.
> >
> > I tried to adapt it to avx2, you can test following
> > http://kam.mff.cuni.cz/~ondra/benchmark_string/strstr_profile250813.tar.bz2
> >
> > I am collecting data of strstr usage in wild. I need to find program
> > that heavily uses strstr A gcc benchmark mostly catches strstr used by
> > linker. I could still get 10% improvement there but it is hard to get
> > more as around half of calls are strstr(string,"=") or strstr(string,",").
> > Another common call is strstr(s,"selinux").
> >
> >
> > Then there is second problem that sse4_2 version is not written properly
> > and exhibits quadratic behaviour.
> >
> > This could be solved by standard buy or rent techique which I employ.
> > For any position p there could be only p+64n+512 comparisons until I
> > switch to two way algorithm which gives linear complexity.
> >
> > I also removed strcasestr as I do not have implementation yet but it
> > should be similar. Main question here is if for all locales it is safe
> > to assume that only case conversion for characters 0-127 is a-z <-> A-Z
> > Then I could vectorize conversion for most cases which would give
> > noticable speeedup. Otherwise I would need to check locale if this
> > holds.
> >
> > Passes tests, it needed lot of manual editing to optimize so it should
> > be checked carefully.
> >
> > >From this I will derive a ssse3 version, shift sse2 version and memmem.
> > Do you see any optimization oppurtinity?
> >
> > Ondra
> >
> > * sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S: New file
> > * sysdeps/x86_64/multiarch/strstr-c.c: Moved to ...
> > * sysdeps/x86_64/multiarch/strstr.c: ... here.
> > (strstr): Add __strstr_sse2_unaligned ifunc.
> > * sysdeps/x86_64/multiarch/strcasestr-c.c: Moved to ...
> > * sysdeps/x86_64/multiarch/strcasestr.c ... here.
> > (strcasestr): Remove __strcasestr_sse42 ifunc.
> > * sysdeps/x86_64/multiarch/strcasestr-nonascii.c: Remove.
> > * sysdeps/x86_64/multiarch/ifunc-impl-list.c: Update.
> > * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Update.
> >
> >
> > ---
> > sysdeps/x86_64/multiarch/Makefile | 10 +-
> > sysdeps/x86_64/multiarch/ifunc-impl-list.c | 4 +-
> > sysdeps/x86_64/multiarch/strcasestr-c.c | 19 --
> > sysdeps/x86_64/multiarch/strcasestr-nonascii.c | 50 ---
> > sysdeps/x86_64/multiarch/strcasestr.c | 23 +-
> > sysdeps/x86_64/multiarch/strstr-c.c | 47 ---
> > sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S | 381 ++++++++++++++++++++++
> > sysdeps/x86_64/multiarch/strstr.c | 388 ++---------------------
> > 8 files changed, 428 insertions(+), 494 deletions(-)
> > delete mode 100644 sysdeps/x86_64/multiarch/strcasestr-c.c
> > delete mode 100644 sysdeps/x86_64/multiarch/strcasestr-nonascii.c
> > delete mode 100644 sysdeps/x86_64/multiarch/strstr-c.c
> > create mode 100644 sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S
> >
> > diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> > index 203d16e..146e800 100644
> > --- a/sysdeps/x86_64/multiarch/Makefile
> > +++ b/sysdeps/x86_64/multiarch/Makefile
> > @@ -9,22 +9,20 @@ ifeq ($(subdir),string)
> > sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3 \
> > strend-sse4 memcmp-sse4 memcpy-ssse3 memcpy-sse2-unaligned mempcpy-ssse3 \
> > memmove-ssse3 memcpy-ssse3-back mempcpy-ssse3-back \
> > - memmove-ssse3-back strcasestr-nonascii strcasecmp_l-ssse3 \
> > + memmove-ssse3-back strcasecmp_l-ssse3 \
> > strncase_l-ssse3 strcat-ssse3 strncat-ssse3\
> > strcpy-ssse3 strncpy-ssse3 stpcpy-ssse3 stpncpy-ssse3 \
> > strcpy-sse2-unaligned strncpy-sse2-unaligned \
> > stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
> > strcat-sse2-unaligned strncat-sse2-unaligned \
> > - strrchr-sse2-no-bsf strchr-sse2-no-bsf memcmp-ssse3
> > + strrchr-sse2-no-bsf strchr-sse2-no-bsf memcmp-ssse3 \
> > + strstr-sse2-unaligned
> > ifeq (yes,$(config-cflags-sse4))
> > -sysdep_routines += strcspn-c strpbrk-c strspn-c strstr-c strcasestr-c varshift
> > +sysdep_routines += strcspn-c strpbrk-c strspn-c varshift
> > CFLAGS-varshift.c += -msse4
> > CFLAGS-strcspn-c.c += -msse4
> > CFLAGS-strpbrk-c.c += -msse4
> > CFLAGS-strspn-c.c += -msse4
> > -CFLAGS-strstr.c += -msse4
> > -CFLAGS-strcasestr.c += -msse4
> > -CFLAGS-strcasestr-nonascii.c += -msse4
> > endif
> > endif
> >
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > index 28d3579..0eaddc7 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > @@ -104,8 +104,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >
> > /* Support sysdeps/x86_64/multiarch/strcasestr.c. */
> > IFUNC_IMPL (i, name, strcasestr,
> > - IFUNC_IMPL_ADD (array, i, strcasestr, HAS_SSE4_2,
> > - __strcasestr_sse42)
> > IFUNC_IMPL_ADD (array, i, strcasestr, 1, __strcasestr_sse2))
> >
> > /* Support sysdeps/x86_64/multiarch/strcat.S. */
> > @@ -196,7 +194,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >
> > /* Support sysdeps/x86_64/multiarch/strstr-c.c. */
> > IFUNC_IMPL (i, name, strstr,
> > - IFUNC_IMPL_ADD (array, i, strstr, HAS_SSE4_2, __strstr_sse42)
> > + IFUNC_IMPL_ADD (array, i, strstr, 1, __strstr_sse2_unaligned)
> > IFUNC_IMPL_ADD (array, i, strstr, 1, __strstr_sse2))
> >
> > /* Support sysdeps/x86_64/multiarch/wcscpy.S. */
> > diff --git a/sysdeps/x86_64/multiarch/strcasestr-c.c b/sysdeps/x86_64/multiarch/strcasestr-c.c
> > deleted file mode 100644
> > index c13a4c4..0000000
> > --- a/sysdeps/x86_64/multiarch/strcasestr-c.c
> > +++ /dev/null
> > @@ -1,19 +0,0 @@
> > -/* Multiple versions of strcasestr
> > - All versions must be listed in ifunc-impl-list.c. */
> > -
> > -#include "init-arch.h"
> > -
> > -#define STRCASESTR __strcasestr_sse2
> > -
> > -#include "string/strcasestr.c"
> > -
> > -extern char *__strcasestr_sse42 (const char *, const char *) attribute_hidden;
> > -extern __typeof (__strcasestr_sse2) __strcasestr_sse2 attribute_hidden;
> > -
> > -#if 1
> > -libc_ifunc (__strcasestr,
> > - HAS_SSE4_2 ? __strcasestr_sse42 : __strcasestr_sse2);
> > -#else
> > -libc_ifunc (__strcasestr,
> > - 0 ? __strcasestr_sse42 : __strcasestr_sse2);
> > -#endif
> > diff --git a/sysdeps/x86_64/multiarch/strcasestr-nonascii.c b/sysdeps/x86_64/multiarch/strcasestr-nonascii.c
> > deleted file mode 100644
> > index 032a642..0000000
> > --- a/sysdeps/x86_64/multiarch/strcasestr-nonascii.c
> > +++ /dev/null
> > @@ -1,50 +0,0 @@
> > -/* strstr with SSE4.2 intrinsics
> > - Copyright (C) 2010-2013 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 <ctype.h>
> > -#include <xmmintrin.h>
> > -
> > -
> > -/* Similar to __m128i_strloadu. Convert to lower case for none-POSIX/C
> > - locale. */
> > -static __m128i
> > -__m128i_strloadu_tolower (const unsigned char *p)
> > -{
> > - union
> > - {
> > - char b[16];
> > - __m128i x;
> > - } u;
> > -
> > - for (int i = 0; i < 16; ++i)
> > - if (p[i] == 0)
> > - {
> > - u.b[i] = 0;
> > - break;
> > - }
> > - else
> > - u.b[i] = tolower (p[i]);
> > -
> > - return u.x;
> > -}
> > -
> > -
> > -#define STRCASESTR_NONASCII
> > -#define USE_AS_STRCASESTR
> > -#define STRSTR_SSE42 __strcasestr_sse42_nonascii
> > -#include "strstr.c"
> > diff --git a/sysdeps/x86_64/multiarch/strcasestr.c b/sysdeps/x86_64/multiarch/strcasestr.c
> > index d1cfb3b..2c2454a 100644
> > --- a/sysdeps/x86_64/multiarch/strcasestr.c
> > +++ b/sysdeps/x86_64/multiarch/strcasestr.c
> > @@ -1,7 +1,18 @@
> > -extern char *__strcasestr_sse42_nonascii (const unsigned char *s1,
> > - const unsigned char *s2)
> > - attribute_hidden;
> > +/* Multiple versions of strcasestr
> > + All versions must be listed in ifunc-impl-list.c. */
> >
> > -#define USE_AS_STRCASESTR
> > -#define STRSTR_SSE42 __strcasestr_sse42
> > -#include "strstr.c"
> > +#include "init-arch.h"
> > +
> > +#define STRCASESTR __strcasestr_sse2
> > +
> > +#include "string/strcasestr.c"
> > +
> > +extern __typeof (__strcasestr_sse2) __strcasestr_sse2 attribute_hidden;
> > +
> > +#if 1
> > +libc_ifunc (__strcasestr,
> > + __strcasestr_sse2);
> > +#else
> > +libc_ifunc (__strcasestr,
> > + 0 ? __strcasestr_sse42 : __strcasestr_sse2);
> > +#endif
> > diff --git a/sysdeps/x86_64/multiarch/strstr-c.c b/sysdeps/x86_64/multiarch/strstr-c.c
> > deleted file mode 100644
> > index 42bbe48..0000000
> > --- a/sysdeps/x86_64/multiarch/strstr-c.c
> > +++ /dev/null
> > @@ -1,47 +0,0 @@
> > -/* Multiple versions of strstr.
> > - All versions must be listed in ifunc-impl-list.c.
> > - Copyright (C) 2012-2013 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/>. */
> > -
> > -/* Redefine strstr so that the compiler won't complain about the type
> > - mismatch with the IFUNC selector in strong_alias, below. */
> > -#undef strstr
> > -#define strstr __redirect_strstr
> > -#include <string.h>
> > -#undef strstr
> > -
> > -#define STRSTR __strstr_sse2
> > -#ifdef SHARED
> > -# undef libc_hidden_builtin_def
> > -# define libc_hidden_builtin_def(name) \
> > - __hidden_ver1 (__strstr_sse2, __GI_strstr, __strstr_sse2);
> > -#endif
> > -
> > -#include "string/strstr.c"
> > -
> > -extern __typeof (__redirect_strstr) __strstr_sse42 attribute_hidden;
> > -extern __typeof (__redirect_strstr) __strstr_sse2 attribute_hidden;
> > -
> > -#include "init-arch.h"
> > -
> > -/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
> > - ifunc symbol properly. */
> > -extern __typeof (__redirect_strstr) __libc_strstr;
> > -libc_ifunc (__libc_strstr, HAS_SSE4_2 ? __strstr_sse42 : __strstr_sse2)
> > -
> > -#undef strstr
> > -strong_alias (__libc_strstr, strstr)
> > diff --git a/sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S
> > new file mode 100644
> > index 0000000..6c134fa
> > --- /dev/null
> > +++ b/sysdeps/x86_64/multiarch/strstr-sse2-unaligned.S
> > @@ -0,0 +1,381 @@
> > +/* strstr with unaligned loads
> > + Copyright (C) 2009-2013 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>
> > +
> > +#ifndef ALIGN
> > +# define ALIGN(n) .p2align n
> > +#endif
> > +
> > +
> > +ENTRY(__strstr_sse2_unaligned)
> > + movzbl (%rsi), %eax
> > + testb %al, %al
> > + je L(empty)
> > + movzbl 1(%rsi), %edx
> > + testb %dl, %dl
> > + je L(strchr)
> > + movd %eax, %xmm1
> > + movd %edx, %xmm2
> > + movq %rdi, %rax
> > + andl $4095, %eax
> > + punpcklbw %xmm1, %xmm1
> > + cmpq $4031, %rax
> > + punpcklbw %xmm2, %xmm2
> > + punpcklwd %xmm1, %xmm1
> > + punpcklwd %xmm2, %xmm2
> > + pshufd $0, %xmm1, %xmm1
> > + pshufd $0, %xmm2, %xmm2
> > + ja L(cross_page)
> > + movdqu (%rdi), %xmm3
> > + pxor %xmm5, %xmm5
> > + movdqu 1(%rdi), %xmm4
> > + movdqa %xmm3, %xmm6
> > + pcmpeqb %xmm1, %xmm3
> > + pcmpeqb %xmm2, %xmm4
> > + movdqu 16(%rdi), %xmm0
> > + pcmpeqb %xmm5, %xmm6
> > + pminub %xmm4, %xmm3
> > + movdqa %xmm3, %xmm4
> > + movdqu 17(%rdi), %xmm3
> > + pcmpeqb %xmm0, %xmm5
> > + pcmpeqb %xmm2, %xmm3
> > + por %xmm6, %xmm4
> > + pcmpeqb %xmm1, %xmm0
> > + pminub %xmm3, %xmm0
> > + por %xmm5, %xmm0
> > + pmovmskb %xmm4, %r8d
> > + pmovmskb %xmm0, %eax
> > + salq $16, %rax
> > + orq %rax, %r8
> > + je L(next_32_bytes)
> > +L(next_pair_index):
> > + bsf %r8, %rax
> > + addq %rdi, %rax
> > + cmpb $0, (%rax)
> > + je L(zero1)
> > + movzbl 2(%rsi), %edx
> > + testb %dl, %dl
> > + je L(found1)
> > + cmpb 2(%rax), %dl
> > + jne L(next_pair)
> > + xorl %edx, %edx
> > + jmp L(pair_loop_start)
> > +
> > + ALIGN (4)
> > +L(strchr):
> > + movzbl %al, %esi
> > + jmp __strchr_sse2
> > +
> > + ALIGN (4)
> > +L(pair_loop):
> > + addq $1, %rdx
> > + cmpb 2(%rax,%rdx), %cl
> > + jne L(next_pair)
> > +L(pair_loop_start):
> > + movzbl 3(%rsi,%rdx), %ecx
> > + testb %cl, %cl
> > + jne L(pair_loop)
> > +L(found1):
> > + ret
> > +L(zero1):
> > + xorl %eax, %eax
> > + ret
> > +
> > + ALIGN (4)
> > +L(next_pair):
> > + leaq -1(%r8), %rax
> > + andq %rax, %r8
> > + jne L(next_pair_index)
> > +
> > + ALIGN (4)
> > +L(next_32_bytes):
> > + movdqu 32(%rdi), %xmm3
> > + pxor %xmm5, %xmm5
> > + movdqu 33(%rdi), %xmm4
> > + movdqa %xmm3, %xmm6
> > + pcmpeqb %xmm1, %xmm3
> > + pcmpeqb %xmm2, %xmm4
> > + movdqu 48(%rdi), %xmm0
> > + pcmpeqb %xmm5, %xmm6
> > + pminub %xmm4, %xmm3
> > + movdqa %xmm3, %xmm4
> > + movdqu 49(%rdi), %xmm3
> > + pcmpeqb %xmm0, %xmm5
> > + pcmpeqb %xmm2, %xmm3
> > + por %xmm6, %xmm4
> > + pcmpeqb %xmm1, %xmm0
> > + pminub %xmm3, %xmm0
> > + por %xmm5, %xmm0
> > + pmovmskb %xmm4, %eax
> > + salq $32, %rax
> > + pmovmskb %xmm0, %r8d
> > + salq $48, %r8
> > + orq %rax, %r8
> > + je L(loop_header)
> > +L(next_pair2_index):
> > + bsfq %r8, %rax
> > + addq %rdi, %rax
> > + cmpb $0, (%rax)
> > + je L(zero2)
> > + movzbl 2(%rsi), %edx
> > + testb %dl, %dl
> > + je L(found2)
> > + cmpb 2(%rax), %dl
> > + jne L(next_pair2)
> > + xorl %edx, %edx
> > + jmp L(pair_loop2_start)
> > +
> > + ALIGN (4)
> > +L(pair_loop2):
> > + addq $1, %rdx
> > + cmpb 2(%rax,%rdx), %cl
> > + jne L(next_pair2)
> > +L(pair_loop2_start):
> > + movzbl 3(%rsi,%rdx), %ecx
> > + testb %cl, %cl
> > + jne L(pair_loop2)
> > +L(found2):
> > + ret
> > + L(zero2):
> > + xorl %eax, %eax
> > + ret
> > +L(empty):
> > + mov %rdi, %rax
> > + ret
> > +
> > + ALIGN (4)
> > +L(next_pair2):
> > + leaq -1(%r8), %rax
> > + andq %rax, %r8
> > + jne L(next_pair2_index)
> > +L(loop_header):
> > + movq $-512, %r11
> > + movq %rdi, %r9
> > +
> > + pxor %xmm7, %xmm7
> > + andq $-64, %rdi
> > +
> > + ALIGN(4)
> > +L(loop):
> > + movdqa 64(%rdi), %xmm3
> > + movdqu 63(%rdi), %xmm6
> > + movdqa %xmm3, %xmm0
> > + pxor %xmm2, %xmm3
> > + pxor %xmm1, %xmm6
> > + movdqa 80(%rdi), %xmm10
> > + por %xmm3, %xmm6
> > + pminub %xmm10, %xmm0
> > + movdqu 79(%rdi), %xmm3
> > + pxor %xmm2, %xmm10
> > + pxor %xmm1, %xmm3
> > + movdqa 96(%rdi), %xmm9
> > + por %xmm10, %xmm3
> > + pminub %xmm9, %xmm0
> > + pxor %xmm2, %xmm9
> > + movdqa 112(%rdi), %xmm8
> > + addq $64, %rdi
> > + pminub %xmm6, %xmm3
> > + movdqu 31(%rdi), %xmm4
> > + pminub %xmm8, %xmm0
> > + pxor %xmm2, %xmm8
> > + pxor %xmm1, %xmm4
> > + por %xmm9, %xmm4
> > + pminub %xmm4, %xmm3
> > + movdqu 47(%rdi), %xmm5
> > + pxor %xmm1, %xmm5
> > + por %xmm8, %xmm5
> > + pminub %xmm5, %xmm3
> > + pminub %xmm3, %xmm0
> > + pcmpeqb %xmm7, %xmm0
> > + pmovmskb %xmm0, %eax
> > + testl %eax, %eax
> > + je L(loop)
> > + pminub (%rdi), %xmm6
> > + pminub 32(%rdi),%xmm4
> > + pminub 48(%rdi),%xmm5
> > + pcmpeqb %xmm7, %xmm6
> > + pcmpeqb %xmm7, %xmm5
> > + pmovmskb %xmm6, %edx
> > + movdqa 16(%rdi), %xmm8
> > + pcmpeqb %xmm7, %xmm4
> > + movdqu 15(%rdi), %xmm0
> > + pmovmskb %xmm5, %r8d
> > + movdqa %xmm8, %xmm3
> > + pmovmskb %xmm4, %ecx
> > + pcmpeqb %xmm1,%xmm0
> > + pcmpeqb %xmm2,%xmm3
> > + salq $32, %rcx
> > + pcmpeqb %xmm7,%xmm8
> > + salq $48, %r8
> > + pminub %xmm0,%xmm3
> > + orq %rcx, %rdx
> > + por %xmm3,%xmm8
> > + orq %rdx, %r8
> > + pmovmskb %xmm8, %eax
> > + salq $16, %rax
> > + orq %rax, %r8
> > +L(next_pair_index3):
> > + bsfq %r8, %rcx
> > + addq %rdi, %rcx
> > + cmpb $0, (%rcx)
> > + je L(zero)
> > + xorl %eax, %eax
> > + movzbl 2(%rsi), %edx
> > + testb %dl, %dl
> > + je L(success3)
> > + cmpb 1(%rcx), %dl
> > + jne L(next_pair3)
> > + jmp L(pair_loop_start3)
> > +
> > + ALIGN (4)
> > +L(pair_loop3):
> > + addq $1, %rax
> > + cmpb 1(%rcx,%rax), %dl
> > + jne L(next_pair3)
> > +L(pair_loop_start3):
> > + movzbl 3(%rsi,%rax), %edx
> > + testb %dl, %dl
> > + jne L(pair_loop3)
> > +L(success3):
> > + lea -1(%rcx), %rax
> > + ret
> > +
> > + ALIGN (4)
> > +L(next_pair3):
> > + addq %rax, %r11
> > + movq %rdi, %rax
> > + subq %r9, %rax
> > + cmpq %r11, %rax
> > + jl L(switch_strstr)
> > + leaq -1(%r8), %rax
> > + andq %rax, %r8
> > + jne L(next_pair_index3)
> > + jmp L(loop)
> > +
> > + ALIGN (4)
> > +L(switch_strstr):
> > + movq %rdi, %rdi
> > + jmp __strstr_sse2
> > +
> > +
> > + ALIGN (4)
> > +L(cross_page):
> > +
> > + movq %rdi, %rax
> > + pxor %xmm0, %xmm0
> > + andq $-64, %rax
> > + movdqa (%rax), %xmm3
> > + movdqu -1(%rax), %xmm4
> > + movdqa %xmm3, %xmm8
> > + movdqa 16(%rax), %xmm5
> > + pcmpeqb %xmm1, %xmm4
> > + pcmpeqb %xmm0, %xmm8
> > + pcmpeqb %xmm2, %xmm3
> > + movdqa %xmm5, %xmm7
> > + pminub %xmm4, %xmm3
> > + movdqu 15(%rax), %xmm4
> > + pcmpeqb %xmm0, %xmm7
> > + por %xmm3, %xmm8
> > + movdqa %xmm5, %xmm3
> > + movdqa 32(%rax), %xmm5
> > + pcmpeqb %xmm1, %xmm4
> > + pcmpeqb %xmm2, %xmm3
> > + movdqa %xmm5, %xmm6
> > + pmovmskb %xmm8, %ecx
> > + pminub %xmm4, %xmm3
> > + movdqu 31(%rax), %xmm4
> > + por %xmm3, %xmm7
> > + movdqa %xmm5, %xmm3
> > + pcmpeqb %xmm0, %xmm6
> > + movdqa 48(%rax), %xmm5
> > + pcmpeqb %xmm1, %xmm4
> > + pmovmskb %xmm7, %r8d
> > + pcmpeqb %xmm2, %xmm3
> > + pcmpeqb %xmm5, %xmm0
> > + pminub %xmm4, %xmm3
> > + movdqu 47(%rax), %xmm4
> > + por %xmm3, %xmm6
> > + movdqa %xmm5, %xmm3
> > + salq $16, %r8
> > + pcmpeqb %xmm1, %xmm4
> > + pcmpeqb %xmm2, %xmm3
> > + pmovmskb %xmm6, %r10d
> > + pminub %xmm4, %xmm3
> > + por %xmm3, %xmm0
> > + salq $32, %r10
> > + orq %r10, %r8
> > + orq %rcx, %r8
> > + movl %edi, %ecx
> > + pmovmskb %xmm0, %edx
> > + subl %eax, %ecx
> > + salq $48, %rdx
> > + orq %rdx, %r8
> > + shrq %cl, %r8
> > + je L(loop_header)
> > +L(next_pair_index4):
> > + bsfq %r8, %rax
> > + addq %rdi, %rax
> > + cmpb $0, (%rax)
> > + je L(zero)
> > +
> > + cmpq %rax,%rdi
> > + je L(next_pair4)
> > +
> > + movzbl 2(%rsi), %edx
> > + testb %dl, %dl
> > + je L(found3)
> > + cmpb 1(%rax), %dl
> > + jne L(next_pair4)
> > + xorl %edx, %edx
> > + jmp L(pair_loop_start4)
> > +
> > +
> > + ALIGN (4)
> > +L(pair_loop4):
> > + addq $1, %rdx
> > + cmpb 1(%rax,%rdx), %cl
> > + jne L(next_pair4)
> > +L(pair_loop_start4):
> > + movzbl 3(%rsi,%rdx), %ecx
> > + testb %cl, %cl
> > + jne L(pair_loop4)
> > +L(found3):
> > + subq $1, %rax
> > + ret
> > +
> > +ALIGN (4)
> > +L(next_pair4):
> > + leaq -1(%r8), %rax
> > + andq %rax, %r8
> > + jne L(next_pair_index4)
> > + jmp L(loop_header)
> > +
> > + ALIGN (4)
> > +L(found):
> > + rep
> > + ret
> > +
> > + ALIGN (4)
> > +L(zero):
> > + xorl %eax, %eax
> > + ret
> > +
> > +
> > +END(__strstr_sse2_unaligned)
> > diff --git a/sysdeps/x86_64/multiarch/strstr.c b/sysdeps/x86_64/multiarch/strstr.c
> > index cd63b68..fbff3a8 100644
> > --- a/sysdeps/x86_64/multiarch/strstr.c
> > +++ b/sysdeps/x86_64/multiarch/strstr.c
> > @@ -1,6 +1,6 @@
> > -/* strstr with SSE4.2 intrinsics
> > - Copyright (C) 2009-2013 Free Software Foundation, Inc.
> > - Contributed by Intel Corporation.
> > +/* Multiple versions of strstr.
> > + All versions must be listed in ifunc-impl-list.c.
> > + Copyright (C) 2012-2013 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
> > @@ -17,369 +17,31 @@
> > License along with the GNU C Library; if not, see
> > <http://www.gnu.org/licenses/>. */
> >
> > -#include <nmmintrin.h>
> > -#include "varshift.h"
> > -
> > -#ifndef STRSTR_SSE42
> > -# define STRSTR_SSE42 __strstr_sse42
> > -#endif
> > -
> > -#ifdef USE_AS_STRCASESTR
> > -# include <ctype.h>
> > -# include <locale/localeinfo.h>
> > -
> > -# define LOADBYTE(C) tolower (C)
> > -# define CMPBYTE(C1, C2) (tolower (C1) == tolower (C2))
> > -#else
> > -# define LOADBYTE(C) (C)
> > -# define CMPBYTE(C1, C2) ((C1) == (C2))
> > -#endif
> > -
> > -/* We use 0xe ordered-compare:
> > - _SIDD_SBYTE_OPS
> > - | _SIDD_CMP_EQUAL_ORDER
> > - | _SIDD_LEAST_SIGNIFICANT
> > - on pcmpistri to do the scanning and string comparsion requirements of
> > - sub-string match. In the scanning phase, we process Cflag and ECX
> > - index to locate the first fragment match; once the first fragment
> > - match position has been identified, we do comparison of subsequent
> > - string fragments until we can conclude false or true match; whe
> > - n concluding a false match, we may need to repeat scanning process
> > - from next relevant offset in the target string.
> > -
> > - In the scanning phase we have 4 cases:
> > - case ECX CFlag ZFlag SFlag
> > - 1 16 0 0 0
> > - 2a 16 0 0 1
> > - 2b 16 0 1 0
> > - 2c 16 0 1 1
> > -
> > - 1. No ordered-comparison match, both 16B fragments are valid, so
> > - continue to next fragment.
> > - 2. No ordered-comparison match, there is EOS in either fragment,
> > - 2a. Zflg = 0, Sflg = 1, we continue
> > - 2b. Zflg = 1, Sflg = 0, we conclude no match and return.
> > - 2c. Zflg = 1, sflg = 1, lenth determine match or no match
> > -
> > - In the string comparison phase, the 1st fragment match is fixed up
> > - to produce ECX = 0. Subsequent fragment compare of nonzero index
> > - and no match conclude a false match.
> > -
> > - case ECX CFlag ZFlag SFlag
> > - 3 X 1 0 0/1
> > - 4a 0 1 0 0
> > - 4b 0 1 0 1
> > - 4c 0 < X 1 0 0/1
> > - 5 16 0 1 0
> > -
> > - 3. An initial ordered-comparison fragment match, we fix up to do
> > - subsequent string comparison
> > - 4a. Continuation of fragment comparison of a string compare.
> > - 4b. EOS reached in the reference string, we conclude true match and
> > - return
> > - 4c. String compare failed if index is nonzero, we need to go back to
> > - scanning
> > - 5. failed string compare, go back to scanning
> > - */
> > -
> > -#if !(defined USE_AS_STRCASESTR && defined STRCASESTR_NONASCII)
> > -/* Simple replacement of movdqu to address 4KB boundary cross issue.
> > - If EOS occurs within less than 16B before 4KB boundary, we don't
> > - cross to next page. */
> > -static __m128i
> > -__m128i_strloadu (const unsigned char * p, __m128i zero)
> > -{
> > - if (__builtin_expect ((int) ((size_t) p & 0xfff) > 0xff0, 0))
> > - {
> > - size_t offset = ((size_t) p & (16 - 1));
> > - __m128i a = _mm_load_si128 ((__m128i *) (p - offset));
> > - int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (a, zero));
> > - if ((bmsk >> offset) != 0)
> > - return __m128i_shift_right (a, offset);
> > - }
> > - return _mm_loadu_si128 ((__m128i *) p);
> > -}
> > -#endif
> > -
> > -#if defined USE_AS_STRCASESTR && !defined STRCASESTR_NONASCII
> > -
> > -/* Similar to __m128i_strloadu. Convert to lower case for POSIX/C
> > - locale and other which have single-byte letters only in the ASCII
> > - range. */
> > -static __m128i
> > -__m128i_strloadu_tolower (const unsigned char *p, __m128i zero, __m128i uclow,
> > - __m128i uchigh, __m128i lcqword)
> > -{
> > - __m128i frag = __m128i_strloadu (p, zero);
> > -
> > - /* Compare if 'Z' > bytes. Inverted way to get a mask for byte <= 'Z'. */
> > - __m128i r2 = _mm_cmpgt_epi8 (uchigh, frag);
> > - /* Compare if bytes are > 'A' - 1. */
> > - __m128i r1 = _mm_cmpgt_epi8 (frag, uclow);
> > - /* Mask byte == ff if byte(r2) <= 'Z' and byte(r1) > 'A' - 1. */
> > - __m128i mask = _mm_and_si128 (r2, r1);
> > - /* Apply lowercase bit 6 mask for above mask bytes == ff. */
> > - return _mm_or_si128 (frag, _mm_and_si128 (mask, lcqword));
> > -}
> > -
> > -#endif
> > -
> > -/* Calculate Knuth-Morris-Pratt string searching algorithm (or KMP
> > - algorithm) overlap for a fully populated 16B vector.
> > - Input parameter: 1st 16Byte loaded from the reference string of a
> > - strstr function.
> > - We don't use KMP algorithm if reference string is less than 16B. */
> > -static int
> > -__inline__ __attribute__ ((__always_inline__,))
> > -KMP16Bovrlap (__m128i s2)
> > -{
> > - __m128i b = _mm_unpacklo_epi8 (s2, s2);
> > - __m128i a = _mm_unpacklo_epi8 (b, b);
> > - a = _mm_shuffle_epi32 (a, 0);
> > - b = _mm_srli_si128 (s2, sizeof (char));
> > - int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (b, a));
> > -
> > - /* _BitScanForward(&k1, bmsk); */
> > - int k1;
> > - __asm ("bsfl %[bmsk], %[k1]" : [k1] "=r" (k1) : [bmsk] "r" (bmsk));
> > - if (!bmsk)
> > - return 16;
> > - else if (bmsk == 0x7fff)
> > - return 1;
> > - else if (!k1)
> > - {
> > - /* There are al least two distinct chars in s2. If byte 0 and 1 are
> > - idential and the distinct value lies farther down, we can deduce
> > - the next byte offset to restart full compare is least no earlier
> > - than byte 3. */
> > - return 3;
> > - }
> > - else
> > - {
> > - /* Byte 1 is not degenerated to byte 0. */
> > - return k1 + 1;
> > - }
> > -}
> > -
> > -char *
> > -__attribute__ ((section (".text.sse4.2")))
> > -STRSTR_SSE42 (const unsigned char *s1, const unsigned char *s2)
> > -{
> > -#define p1 s1
> > - const unsigned char *p2 = s2;
> > -
> > -#ifndef STRCASESTR_NONASCII
> > - if (__builtin_expect (p2[0] == '\0', 0))
> > - return (char *) p1;
> > -
> > - if (__builtin_expect (p1[0] == '\0', 0))
> > - return NULL;
> > -
> > - /* Check if p1 length is 1 byte long. */
> > - if (__builtin_expect (p1[1] == '\0', 0))
> > - return p2[1] == '\0' && CMPBYTE (p1[0], p2[0]) ? (char *) p1 : NULL;
> > -#endif
> > -
> > -#ifdef USE_AS_STRCASESTR
> > -# ifndef STRCASESTR_NONASCII
> > - if (__builtin_expect (_NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_NONASCII_CASE)
> > - != 0, 0))
> > - return __strcasestr_sse42_nonascii (s1, s2);
> > -
> > - const __m128i uclow = _mm_set1_epi8 (0x40);
> > - const __m128i uchigh = _mm_set1_epi8 (0x5b);
> > - const __m128i lcqword = _mm_set1_epi8 (0x20);
> > - const __m128i zero = _mm_setzero_si128 ();
> > -# define strloadu(p) __m128i_strloadu_tolower (p, zero, uclow, uchigh, lcqword)
> > -# else
> > -# define strloadu __m128i_strloadu_tolower
> > -# define zero _mm_setzero_si128 ()
> > -# endif
> > -#else
> > -# define strloadu(p) __m128i_strloadu (p, zero)
> > - const __m128i zero = _mm_setzero_si128 ();
> > +/* Redefine strstr so that the compiler won't complain about the type
> > + mismatch with the IFUNC selector in strong_alias, below. */
> > +#undef strstr
> > +#define strstr __redirect_strstr
> > +#include <string.h>
> > +#undef strstr
> > +
> > +#define STRSTR __strstr_sse2
> > +#ifdef SHARED
> > +# undef libc_hidden_builtin_def
> > +# define libc_hidden_builtin_def(name) \
> > + __hidden_ver1 (__strstr_sse2, __GI_strstr, __strstr_sse2);
> > #endif
> >
> > - /* p1 > 1 byte long. Load up to 16 bytes of fragment. */
> > - __m128i frag1 = strloadu (p1);
> > -
> > - __m128i frag2;
> > - if (p2[1] != '\0')
> > - /* p2 is > 1 byte long. */
> > - frag2 = strloadu (p2);
> > - else
> > - frag2 = _mm_insert_epi8 (zero, LOADBYTE (p2[0]), 0);
> > -
> > - /* Unsigned bytes, equal order, does frag2 has null? */
> > - int cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - int cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - int cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - int cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
> > - if (cmp_s & cmp_c)
> > - {
> > - int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (frag2, zero));
> > - int len;
> > - __asm ("bsfl %[bmsk], %[len]"
> > - : [len] "=r" (len) : [bmsk] "r" (bmsk));
> > - p1 += cmp;
> > - if ((len + cmp) <= 16)
> > - return (char *) p1;
> > -
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - if ((len + cmp) <= 16)
> > - return (char *) p1 + cmp;
> > - }
> > -
> > - if (cmp_s)
> > - {
> > - /* Adjust addr for 16B alginment in ensuing loop. */
> > - while (!cmp_z)
> > - {
> > - p1 += cmp;
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - /* Because s2 < 16 bytes and we adjusted p1 by non-zero cmp
> > - once already, this time cmp will be zero and we can exit. */
> > - if ((!cmp) & cmp_c)
> > - break;
> > - }
> > -
> > - if (!cmp_c)
> > - return NULL;
> > -
> > - /* Since s2 is less than 16 bytes, com_c is definitive
> > - determination of full match. */
> > - return (char *) p1 + cmp;
> > - }
> > -
> > - /* General case, s2 is at least 16 bytes or more.
> > - First, the common case of false-match at first byte of p2. */
> > - const unsigned char *pt = NULL;
> > - int kmp_fwd = 0;
> > -re_trace:
> > - while (!cmp_c)
> > - {
> > - /* frag1 has null. */
> > - if (cmp_z)
> > - return NULL;
> > -
> > - /* frag 1 has no null, advance 16 bytes. */
> > - p1 += 16;
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > - /* Unsigned bytes, equal order, is there a partial match? */
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - }
> > -
> > - /* Next, handle initial positive match as first byte of p2. We have
> > - a partial fragment match, make full determination until we reached
> > - end of s2. */
> > - if (!cmp)
> > - {
> > - if (cmp_z)
> > - return (char *) p1;
> > -
> > - pt = p1;
> > - p1 += 16;
> > - p2 += 16;
> > - /* Load up to 16 bytes of fragment. */
> > - frag2 = strloadu (p2);
> > - }
> > - else
> > - {
> > - /* Adjust 16B alignment. */
> > - p1 += cmp;
> > - pt = p1;
> > - }
> > -
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > -
> > - /* Unsigned bytes, equal order, does frag2 has null? */
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
> > - while (!(cmp | cmp_z | cmp_s))
> > - {
> > - p1 += 16;
> > - p2 += 16;
> > - /* Load up to 16 bytes of fragment. */
> > - frag2 = strloadu (p2);
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > - /* Unsigned bytes, equal order, does frag2 has null? */
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
> > - }
> > -
> > - /* Full determination yielded a false result, retrace s1 to next
> > - starting position.
> > - Zflg 1 0 1 0/1
> > - Sflg 0 1 1 0/1
> > - cmp na 0 0 >0
> > - action done done continue continue if s2 < s1
> > - false match retrace s1 else false
> > - */
> > -
> > - if (cmp_s & !cmp)
> > - return (char *) pt;
> > - if (cmp_z)
> > - {
> > - if (!cmp_s)
> > - return NULL;
> > -
> > - /* Handle both zero and sign flag set and s1 is shorter in
> > - length. */
> > - int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag2));
> > - int bmsk1 = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag1));
> > - int len;
> > - int len1;
> > - __asm ("bsfl %[bmsk], %[len]"
> > - : [len] "=r" (len) : [bmsk] "r" (bmsk));
> > - __asm ("bsfl %[bmsk1], %[len1]"
> > - : [len1] "=r" (len1) : [bmsk1] "r" (bmsk1));
> > - if (len >= len1)
> > - return NULL;
> > - }
> > - else if (!cmp)
> > - return (char *) pt;
> > -
> > - /* Otherwise, we have to retrace and continue. Default of multiple
> > - paths that need to retrace from next byte in s1. */
> > - p2 = s2;
> > - frag2 = strloadu (p2);
> > -
> > - if (!kmp_fwd)
> > - kmp_fwd = KMP16Bovrlap (frag2);
> > +#include "string/strstr.c"
> >
> > - /* KMP algorithm predicted overlap needs to be corrected for
> > - partial fragment compare. */
> > - p1 = pt + (kmp_fwd > cmp ? cmp : kmp_fwd);
> > +extern __typeof (__redirect_strstr) __strstr_sse2_unaligned attribute_hidden;
> > +extern __typeof (__redirect_strstr) __strstr_sse2 attribute_hidden;
> >
> > - /* Since s2 is at least 16 bytes long, we're certain there is no
> > - match. */
> > - if (p1[0] == '\0')
> > - return NULL;
> > +#include "init-arch.h"
> >
> > - /* Load up to 16 bytes of fragment. */
> > - frag1 = strloadu (p1);
> > +/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
> > + ifunc symbol properly. */
> > +extern __typeof (__redirect_strstr) __libc_strstr;
> > +libc_ifunc (__libc_strstr, HAS_FAST_UNALIGNED_LOAD ? __strstr_sse2_unaligned : __strstr_sse2)
> >
> > - /* Unsigned bytes, equal order, is there a partial match? */
> > - cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
> > - cmp = _mm_cmpistri (frag2, frag1, 0x0c);
> > - cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
> > - goto re_trace;
> > -}
> > +#undef strstr
> > +strong_alias (__libc_strstr, strstr)
> > --
> > 1.8.3.2
>
> --
>
> The UPS doesn't have a battery backup.
--
The air conditioning water supply pipe ruptured over the machine room