[PATCH v1 09/23] x86: Remove strcspn-sse2.S and use the generic implementation

H.J. Lu hjl.tools@gmail.com
Thu Mar 24 18:57:06 GMT 2022


On Wed, Mar 23, 2022 at 3:00 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> The generic implementation is faster.
>
> geometric_mean(N=20) of all benchmarks New / Original: .678
>
> All string/memory tests pass.
> ---
> Geomtric Mean N=20 runs; All functions page aligned
> len, align1, align2,  pos, New Time / Old Time
>   0,      0,      0,  512,               0.054
>   1,      0,      0,  512,               0.055
>   1,      1,      0,  512,               0.051
>   1,      0,      1,  512,               0.054
>   1,      1,      1,  512,               0.054
>   2,      0,      0,  512,               0.861
>   2,      2,      0,  512,               0.861
>   2,      0,      2,  512,               0.861
>   2,      2,      2,  512,               0.864
>   3,      0,      0,  512,               0.854
>   3,      3,      0,  512,               0.848
>   3,      0,      3,  512,               0.845
>   3,      3,      3,  512,                0.85
>   4,      0,      0,  512,               0.851
>   4,      4,      0,  512,                0.85
>   4,      0,      4,  512,               0.852
>   4,      4,      4,  512,               0.849
>   5,      0,      0,  512,               0.938
>   5,      5,      0,  512,                0.94
>   5,      0,      5,  512,               0.864
>   5,      5,      5,  512,                0.86
>   6,      0,      0,  512,               0.858
>   6,      6,      0,  512,               0.869
>   6,      0,      6,  512,               0.847
>   6,      6,      6,  512,               0.868
>   7,      0,      0,  512,               0.867
>   7,      7,      0,  512,               0.861
>   7,      0,      7,  512,               0.864
>   7,      7,      7,  512,               0.863
>   8,      0,      0,  512,               0.884
>   8,      0,      8,  512,               0.884
>   9,      0,      0,  512,               0.886
>   9,      1,      0,  512,               0.894
>   9,      0,      9,  512,               0.889
>   9,      1,      9,  512,               0.886
>  10,      0,      0,  512,               0.859
>  10,      2,      0,  512,               0.859
>  10,      0,     10,  512,               0.862
>  10,      2,     10,  512,               0.861
>  11,      0,      0,  512,               0.846
>  11,      3,      0,  512,               0.865
>  11,      0,     11,  512,               0.859
>  11,      3,     11,  512,               0.862
>  12,      0,      0,  512,               0.858
>  12,      4,      0,  512,               0.857
>  12,      0,     12,  512,               0.964
>  12,      4,     12,  512,               0.876
>  13,      0,      0,  512,               0.827
>  13,      5,      0,  512,               0.805
>  13,      0,     13,  512,               0.821
>  13,      5,     13,  512,               0.825
>  14,      0,      0,  512,               0.786
>  14,      6,      0,  512,               0.786
>  14,      0,     14,  512,               0.803
>  14,      6,     14,  512,               0.783
>  15,      0,      0,  512,               0.778
>  15,      7,      0,  512,               0.792
>  15,      0,     15,  512,               0.796
>  15,      7,     15,  512,               0.799
>  16,      0,      0,  512,               0.803
>  16,      0,     16,  512,               0.815
>  17,      0,      0,  512,               0.812
>  17,      1,      0,  512,               0.826
>  17,      0,     17,  512,               0.803
>  17,      1,     17,  512,               0.856
>  18,      0,      0,  512,               0.801
>  18,      2,      0,  512,               0.886
>  18,      0,     18,  512,               0.805
>  18,      2,     18,  512,               0.807
>  19,      0,      0,  512,               0.814
>  19,      3,      0,  512,               0.804
>  19,      0,     19,  512,               0.813
>  19,      3,     19,  512,               0.814
>  20,      0,      0,  512,               0.885
>  20,      4,      0,  512,               0.799
>  20,      0,     20,  512,               0.826
>  20,      4,     20,  512,               0.808
>  21,      0,      0,  512,               0.816
>  21,      5,      0,  512,               0.824
>  21,      0,     21,  512,               0.819
>  21,      5,     21,  512,               0.826
>  22,      0,      0,  512,               0.814
>  22,      6,      0,  512,               0.824
>  22,      0,     22,  512,                0.81
>  22,      6,     22,  512,               0.806
>  23,      0,      0,  512,               0.825
>  23,      7,      0,  512,               0.829
>  23,      0,     23,  512,               0.809
>  23,      7,     23,  512,               0.823
>  24,      0,      0,  512,               0.829
>  24,      0,     24,  512,               0.823
>  25,      0,      0,  512,               0.864
>  25,      1,      0,  512,               0.895
>  25,      0,     25,  512,                0.88
>  25,      1,     25,  512,               0.848
>  26,      0,      0,  512,               0.903
>  26,      2,      0,  512,               0.888
>  26,      0,     26,  512,               0.894
>  26,      2,     26,  512,                0.89
>  27,      0,      0,  512,               0.914
>  27,      3,      0,  512,               0.917
>  27,      0,     27,  512,               0.902
>  27,      3,     27,  512,               0.887
>  28,      0,      0,  512,               0.887
>  28,      4,      0,  512,               0.877
>  28,      0,     28,  512,               0.893
>  28,      4,     28,  512,               0.866
>  29,      0,      0,  512,               0.885
>  29,      5,      0,  512,               0.907
>  29,      0,     29,  512,               0.894
>  29,      5,     29,  512,               0.906
>  30,      0,      0,  512,                0.88
>  30,      6,      0,  512,               0.898
>  30,      0,     30,  512,                 0.9
>  30,      6,     30,  512,               0.895
>  31,      0,      0,  512,               0.893
>  31,      7,      0,  512,               0.874
>  31,      0,     31,  512,               0.894
>  31,      7,     31,  512,               0.899
>   4,      0,      0,   32,               0.618
>   4,      1,      0,   32,               0.627
>   4,      0,      1,   32,               0.625
>   4,      1,      1,   32,               0.613
>   4,      0,      0,   64,               0.913
>   4,      2,      0,   64,               0.801
>   4,      0,      2,   64,               0.759
>   4,      2,      2,   64,               0.761
>   4,      0,      0,  128,               0.822
>   4,      3,      0,  128,               0.863
>   4,      0,      3,  128,               0.867
>   4,      3,      3,  128,               0.917
>   4,      0,      0,  256,               0.816
>   4,      4,      0,  256,               0.812
>   4,      0,      4,  256,               0.803
>   4,      4,      4,  256,               0.811
>   4,      5,      0,  512,               0.848
>   4,      0,      5,  512,               0.843
>   4,      5,      5,  512,               0.857
>   4,      0,      0, 1024,               0.886
>   4,      6,      0, 1024,               0.887
>   4,      0,      6, 1024,               0.881
>   4,      6,      6, 1024,               0.873
>   4,      0,      0, 2048,               0.892
>   4,      7,      0, 2048,               0.894
>   4,      0,      7, 2048,                0.89
>   4,      7,      7, 2048,               0.874
>  10,      1,      0,   64,               0.946
>  10,      1,      1,   64,                0.81
>  10,      2,      0,   64,               0.804
>  10,      2,      2,   64,                0.82
>  10,      3,      0,   64,               0.772
>  10,      3,      3,   64,               0.772
>  10,      4,      0,   64,               0.748
>  10,      4,      4,   64,               0.751
>  10,      5,      0,   64,                0.76
>  10,      5,      5,   64,                0.76
>  10,      6,      0,   64,               0.726
>  10,      6,      6,   64,               0.718
>  10,      7,      0,   64,               0.724
>  10,      7,      7,   64,                0.72
>   6,      0,      0,    0,               0.415
>   6,      0,      0,    1,               0.423
>   6,      0,      1,    1,               0.412
>   6,      0,      0,    2,               0.433
>   6,      0,      2,    2,               0.434
>   6,      0,      0,    3,               0.427
>   6,      0,      3,    3,               0.428
>   6,      0,      0,    4,               0.465
>   6,      0,      4,    4,               0.466
>   6,      0,      0,    5,               0.463
>   6,      0,      5,    5,               0.468
>   6,      0,      0,    6,               0.435
>   6,      0,      6,    6,               0.444
>   6,      0,      0,    7,                0.41
>   6,      0,      7,    7,                0.42
>   6,      0,      0,    8,               0.474
>   6,      0,      8,    8,               0.501
>   6,      0,      0,    9,               0.471
>   6,      0,      9,    9,               0.489
>   6,      0,      0,   10,               0.462
>   6,      0,     10,   10,                0.46
>   6,      0,      0,   11,               0.459
>   6,      0,     11,   11,               0.458
>   6,      0,      0,   12,               0.516
>   6,      0,     12,   12,                0.51
>   6,      0,      0,   13,               0.494
>   6,      0,     13,   13,               0.524
>   6,      0,      0,   14,               0.486
>   6,      0,     14,   14,                 0.5
>   6,      0,      0,   15,                0.48
>   6,      0,     15,   15,               0.501
>   6,      0,      0,   16,                0.54
>   6,      0,     16,   16,               0.538
>   6,      0,      0,   17,               0.503
>   6,      0,     17,   17,               0.541
>   6,      0,      0,   18,               0.537
>   6,      0,     18,   18,               0.549
>   6,      0,      0,   19,               0.527
>   6,      0,     19,   19,               0.537
>   6,      0,      0,   20,               0.539
>   6,      0,     20,   20,               0.554
>   6,      0,      0,   21,               0.558
>   6,      0,     21,   21,               0.541
>   6,      0,      0,   22,               0.546
>   6,      0,     22,   22,               0.561
>   6,      0,      0,   23,                0.54
>   6,      0,     23,   23,               0.536
>   6,      0,      0,   24,               0.565
>   6,      0,     24,   24,               0.584
>   6,      0,      0,   25,               0.563
>   6,      0,     25,   25,                0.58
>   6,      0,      0,   26,               0.555
>   6,      0,     26,   26,               0.584
>   6,      0,      0,   27,               0.569
>   6,      0,     27,   27,               0.587
>   6,      0,      0,   28,               0.612
>   6,      0,     28,   28,               0.623
>   6,      0,      0,   29,               0.604
>   6,      0,     29,   29,               0.621
>   6,      0,      0,   30,                0.59
>   6,      0,     30,   30,               0.609
>   6,      0,      0,   31,               0.577
>   6,      0,     31,   31,               0.588
>   6,      0,      0,   32,               0.621
>   6,      0,     32,   32,               0.608
>   6,      0,      0,   33,               0.601
>   6,      0,     33,   33,               0.623
>   6,      0,      0,   34,               0.614
>   6,      0,     34,   34,               0.615
>   6,      0,      0,   35,               0.598
>   6,      0,     35,   35,               0.608
>   6,      0,      0,   36,               0.626
>   6,      0,     36,   36,               0.634
>   6,      0,      0,   37,                0.62
>   6,      0,     37,   37,               0.634
>   6,      0,      0,   38,               0.612
>   6,      0,     38,   38,               0.637
>   6,      0,      0,   39,               0.627
>   6,      0,     39,   39,               0.612
>   6,      0,      0,   40,               0.661
>   6,      0,     40,   40,               0.674
>   6,      0,      0,   41,               0.633
>   6,      0,     41,   41,               0.643
>   6,      0,      0,   42,               0.634
>   6,      0,     42,   42,               0.636
>   6,      0,      0,   43,               0.619
>   6,      0,     43,   43,               0.625
>   6,      0,      0,   44,               0.654
>   6,      0,     44,   44,               0.654
>   6,      0,      0,   45,               0.647
>   6,      0,     45,   45,               0.649
>   6,      0,      0,   46,               0.651
>   6,      0,     46,   46,               0.651
>   6,      0,      0,   47,               0.646
>   6,      0,     47,   47,               0.648
>   6,      0,      0,   48,               0.662
>   6,      0,     48,   48,               0.664
>   6,      0,      0,   49,                0.68
>   6,      0,     49,   49,               0.667
>   6,      0,      0,   50,               0.654
>   6,      0,     50,   50,               0.659
>   6,      0,      0,   51,               0.638
>   6,      0,     51,   51,               0.639
>   6,      0,      0,   52,               0.665
>   6,      0,     52,   52,               0.669
>   6,      0,      0,   53,               0.658
>   6,      0,     53,   53,               0.656
>   6,      0,      0,   54,               0.669
>   6,      0,     54,   54,                0.67
>   6,      0,      0,   55,               0.668
>   6,      0,     55,   55,               0.664
>   6,      0,      0,   56,               0.701
>   6,      0,     56,   56,               0.695
>   6,      0,      0,   57,               0.687
>   6,      0,     57,   57,               0.696
>   6,      0,      0,   58,               0.693
>   6,      0,     58,   58,               0.704
>   6,      0,      0,   59,               0.695
>   6,      0,     59,   59,               0.708
>   6,      0,      0,   60,               0.708
>   6,      0,     60,   60,               0.728
>   6,      0,      0,   61,               0.708
>   6,      0,     61,   61,                0.71
>   6,      0,      0,   62,               0.715
>   6,      0,     62,   62,               0.705
>   6,      0,      0,   63,               0.677
>   6,      0,     63,   63,               0.702
>
>  .../{strcspn-sse2.S => strcspn-sse2.c}        |   8 +-
>  sysdeps/x86_64/strcspn.S                      | 119 ------------------
>  2 files changed, 4 insertions(+), 123 deletions(-)
>  rename sysdeps/x86_64/multiarch/{strcspn-sse2.S => strcspn-sse2.c} (85%)
>  delete mode 100644 sysdeps/x86_64/strcspn.S
>
> diff --git a/sysdeps/x86_64/multiarch/strcspn-sse2.S b/sysdeps/x86_64/multiarch/strcspn-sse2.c
> similarity index 85%
> rename from sysdeps/x86_64/multiarch/strcspn-sse2.S
> rename to sysdeps/x86_64/multiarch/strcspn-sse2.c
> index f97e856e1f..3a04bb39fc 100644
> --- a/sysdeps/x86_64/multiarch/strcspn-sse2.S
> +++ b/sysdeps/x86_64/multiarch/strcspn-sse2.c
> @@ -1,4 +1,4 @@
> -/* strcspn optimized with SSE2.
> +/* strcspn.
>     Copyright (C) 2017-2022 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>
> @@ -19,10 +19,10 @@
>  #if IS_IN (libc)
>
>  # include <sysdep.h>
> -# define strcspn __strcspn_sse2
> +# define STRCSPN __strcspn_sse2
>
>  # undef libc_hidden_builtin_def
> -# define libc_hidden_builtin_def(strcspn)
> +# define libc_hidden_builtin_def(STRCSPN)
>  #endif
>
> -#include <sysdeps/x86_64/strcspn.S>
> +#include <string/strcspn.c>
> diff --git a/sysdeps/x86_64/strcspn.S b/sysdeps/x86_64/strcspn.S
> deleted file mode 100644
> index f3cd86c606..0000000000
> --- a/sysdeps/x86_64/strcspn.S
> +++ /dev/null
> @@ -1,119 +0,0 @@
> -/* strcspn (str, ss) -- Return the length of the initial segment of STR
> -                       which contains no characters from SS.
> -   For AMD x86-64.
> -   Copyright (C) 1994-2022 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
> -   <https://www.gnu.org/licenses/>.  */
> -
> -#include <sysdep.h>
> -#include "asm-syntax.h"
> -
> -       .text
> -ENTRY (strcspn)
> -
> -       movq %rdi, %rdx         /* Save SRC.  */
> -
> -       /* First we create a table with flags for all possible characters.
> -          For the ASCII (7bit/8bit) or ISO-8859-X character sets which are
> -          supported by the C string functions we have 256 characters.
> -          Before inserting marks for the stop characters we clear the whole
> -          table.  */
> -       movq %rdi, %r8                  /* Save value.  */
> -       subq $256, %rsp                 /* Make space for 256 bytes.  */
> -       cfi_adjust_cfa_offset(256)
> -       movl $32,  %ecx                 /* 32*8 bytes = 256 bytes.  */
> -       movq %rsp, %rdi
> -       xorl %eax, %eax                 /* We store 0s.  */
> -       cld
> -       rep
> -       stosq
> -
> -       movq %rsi, %rax                 /* Setup skipset.  */
> -
> -/* For understanding the following code remember that %rcx == 0 now.
> -   Although all the following instruction only modify %cl we always
> -   have a correct zero-extended 64-bit value in %rcx.  */
> -
> -       .p2align 4
> -L(2):  movb (%rax), %cl        /* get byte from skipset */
> -       testb %cl, %cl          /* is NUL char? */
> -       jz L(1)                 /* yes => start compare loop */
> -       movb %cl, (%rsp,%rcx)   /* set corresponding byte in skipset table */
> -
> -       movb 1(%rax), %cl       /* get byte from skipset */
> -       testb $0xff, %cl        /* is NUL char? */
> -       jz L(1)                 /* yes => start compare loop */
> -       movb %cl, (%rsp,%rcx)   /* set corresponding byte in skipset table */
> -
> -       movb 2(%rax), %cl       /* get byte from skipset */
> -       testb $0xff, %cl        /* is NUL char? */
> -       jz L(1)                 /* yes => start compare loop */
> -       movb %cl, (%rsp,%rcx)   /* set corresponding byte in skipset table */
> -
> -       movb 3(%rax), %cl       /* get byte from skipset */
> -       addq $4, %rax           /* increment skipset pointer */
> -       movb %cl, (%rsp,%rcx)   /* set corresponding byte in skipset table */
> -       testb $0xff, %cl        /* is NUL char? */
> -       jnz L(2)                /* no => process next dword from skipset */
> -
> -L(1):  leaq -4(%rdx), %rax     /* prepare loop */
> -
> -       /* We use a neat trick for the following loop.  Normally we would
> -          have to test for two termination conditions
> -          1. a character in the skipset was found
> -          and
> -          2. the end of the string was found
> -          But as a sign that the character is in the skipset we store its
> -          value in the table.  But the value of NUL is NUL so the loop
> -          terminates for NUL in every case.  */
> -
> -       .p2align 4
> -L(3):  addq $4, %rax           /* adjust pointer for full loop round */
> -
> -       movb (%rax), %cl        /* get byte from string */
> -       cmpb %cl, (%rsp,%rcx)   /* is it contained in skipset? */
> -       je L(4)                 /* yes => return */
> -
> -       movb 1(%rax), %cl       /* get byte from string */
> -       cmpb %cl, (%rsp,%rcx)   /* is it contained in skipset? */
> -       je L(5)                 /* yes => return */
> -
> -       movb 2(%rax), %cl       /* get byte from string */
> -       cmpb %cl, (%rsp,%rcx)   /* is it contained in skipset? */
> -       jz L(6)                 /* yes => return */
> -
> -       movb 3(%rax), %cl       /* get byte from string */
> -       cmpb %cl, (%rsp,%rcx)   /* is it contained in skipset? */
> -       jne L(3)                /* no => start loop again */
> -
> -       incq %rax               /* adjust pointer */
> -L(6):  incq %rax
> -L(5):  incq %rax
> -
> -L(4):  addq $256, %rsp         /* remove skipset */
> -       cfi_adjust_cfa_offset(-256)
> -#ifdef USE_AS_STRPBRK
> -       xorl %edx,%edx
> -       orb %cl, %cl            /* was last character NUL? */
> -       cmovzq %rdx, %rax       /* Yes: return NULL */
> -#else
> -       subq %rdx, %rax         /* we have to return the number of valid
> -                                  characters, so compute distance to first
> -                                  non-valid character */
> -#endif
> -       ret
> -END (strcspn)
> -libc_hidden_builtin_def (strcspn)
> --
> 2.25.1
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

-- 
H.J.


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