Re: [PATCH] Multiarch optimization for strspn on POWERPC

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

Hi Vidya,

Pushed as e65caf1f1df4ecc122da3d30689ee2e8e2bd354f , thanks

On 10-03-2014 14:36, R Vidya wrote:
> Hi Adhemerval , fixed it. Please push if OKay.
>
>
> On Monday 10 March 2014 08:09 PM, Adhemerval Zanella wrote:
>> Hi Vidya,
>>
>> Sorry if I didn't catch it early, but just noted some line are not respecting the 80 column
>> requirement from code guidelines, please fix these (example below). Also, I just also noted
>> since you are touching 'string/strspn.c' it is worth of cleanup the old C-style (comment
>> below). With this change I think it is good to push upstream.
>>
>>
>> On 07-03-2014 07:23, R Vidya wrote:
>>> diff --git a/string/strspn.c b/string/strspn.c
>>> index 37e8161..557eec5 100644
>>> --- a/string/strspn.c
>>> +++ b/string/strspn.c
>>> @@ -18,11 +18,14 @@
>>>   #include <string.h>
>>>
>>>   #undef strspn
>>> +#ifndef STRSPN
>>> +#define STRSPN strspn
>>> +#endif
>>>
>>>   /* Return the length of the maximum initial segment
>>>      of S which contains only characters in ACCEPT.  */
>>>   size_t
>>> -strspn (s, accept)
>>> +STRSPN (s, accept)
>>>        const char *s;
>>>        const char *accept;
>>>   {
>> There is no need on using old K&R style, just convert it to STRSPN (const char *s, const char *accept)
>>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> index a03569e..3e8010c 100644
>>> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> @@ -14,7 +14,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
>>>              wcsrchr-ppc64 wcscpy-power7 wcscpy-power6 wcscpy-ppc64 \
>>>              wordcopy-power7 wordcopy-power6 wordcopy-ppc64 \
>>>              strcpy-power7 strcpy-ppc64 stpcpy-power7 stpcpy-ppc64 \
>>> -           strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64
>>> +           strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
>>> +           strspn-power7 strspn-ppc64
>>>
>>>   CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
>>>   CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>>> index 11a3bed..20d7918 100644
>>> --- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>>> @@ -254,5 +254,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>>>             IFUNC_IMPL_ADD (array, i, strncat, 1,
>>>                     __strncat_ppc))
>>>
>>> +  /* Support sysdeps/powerpc/powerpc64/multiarch/strspn.c.  */
>>> +  IFUNC_IMPL (i, name, strspn,
>>> +          IFUNC_IMPL_ADD (array, i, strspn,
>>> +                  hwcap & PPC_FEATURE_HAS_VSX,
>>> +                  __strspn_power7)
>>> +          IFUNC_IMPL_ADD (array, i, strspn, 1,
>>> +                  __strspn_ppc))
>>> +
>>>     return i;
>>>   }
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strspn-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strspn-power7.S
>>> new file mode 100644
>>> index 0000000..889dfee
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strspn-power7.S
>>> @@ -0,0 +1,40 @@
>>> +/* Optimized strspn implementation for POWER7.
>>> +   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>
>>> +
>>> +#undef EALIGN
>>> +#define EALIGN(name, alignt, words)                \
>>> +  .section ".text";                        \
>>> +  ENTRY_2(__strspn_power7)                    \
>>> +  .align ALIGNARG(alignt);                    \
>>> +  EALIGN_W_##words;                        \
>>> +  BODY_LABEL(__strspn_power7):                    \
>>> +  cfi_startproc;                        \
>>> +  LOCALENTRY(__strspn_power7)
>>> +
>>> +#undef END
>>> +#define END(name)                        \
>>> +  cfi_endproc;                            \
>>> +  TRACEBACK(__strspn_power7)                    \
>>> +  END_2(__strspn_power7)
>>> +
>>> +#undef libc_hidden_builtin_def
>>> +#define libc_hidden_builtin_def(name)
>>> +
>>> +#include <sysdeps/powerpc/powerpc64/power7/strspn.S>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strspn-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/strspn-ppc64.c
>>> new file mode 100644
>>> index 0000000..d543772
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strspn-ppc64.c
>>> @@ -0,0 +1,33 @@
>>> +/* 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 <string.h>
>>> +
>>> +#define STRSPN __strspn_ppc
>>> +#undef weak_alias
>>> +#define weak_alias(name, aliasname) \
>>> +  extern __typeof (__strspn_ppc) aliasname \
>>> +    __attribute__ ((weak, alias ("__strspn_ppc")));
>>> +#if !defined(NOT_IN_libc) && defined(SHARED)
>>> +# undef libc_hidden_builtin_def
>>> +# define libc_hidden_builtin_def(name) \
>>> +  __hidden_ver1(__strspn_ppc, __GI_strspn, __strspn_ppc);
>>> +#endif
>>> +
>>> +extern __typeof (strspn) __strspn_ppc attribute_hidden;
>>> +
>>> +#include <string/strspn.c>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strspn.c b/sysdeps/powerpc/powerpc64/multiarch/strspn.c
>>> new file mode 100644
>>> index 0000000..44945f3
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strspn.c
>>> @@ -0,0 +1,31 @@
>>> +/* Multiple versions of strspn. PowerPC64 version.
>>> +   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/>.  */
>>> +
>>> +#if defined SHARED && !defined NOT_IN_libc
>>> +# include <string.h>
>>> +# include <shlib-compat.h>
>>> +# include "init-arch.h"
>>> +
>>> +extern __typeof (strspn) __strspn_ppc attribute_hidden;
>>> +extern __typeof (strspn) __strspn_power7 attribute_hidden;
>>> +
>>> +libc_ifunc (strspn,
>>> +            (hwcap & PPC_FEATURE_HAS_VSX)
>>> +            ? __strspn_power7
>>> +            : __strspn_ppc);
>>> +#endif
>>> diff --git a/sysdeps/powerpc/powerpc64/power7/strspn.S b/sysdeps/powerpc/powerpc64/power7/strspn.S
>>> new file mode 100644
>>> index 0000000..876e9cc
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/power7/strspn.S
>>> @@ -0,0 +1,148 @@
>>> +/* Optimized strspn implementation for PowerPC64/POWER7.
>>> +
>>> +   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/>.  */
>>> +
>>> +/* size_t [r3] strspn (const char *string [r3],
>>> +                       const char *needleAccept [r4]  */
>>> +
>>> +/* Performance gains are grabbed through following techniques:
>>> +
>>> +   > hashing of needle.
>>> +   > hashing avoids scanning of duplicate entries in needle across the string.
>>> +   > initializing the hash table with Vector instructions by quadword access.
>>> +   > unrolling when scanning for character in string across hash table.  */
>>> +
>>> +/* Algorithm is as below:
>>> +   1. A empty hash table/dictionary is created comprising of 256 ascii character set
>> Here it is an example of the column limit limit, please break it to fix 80 column.
>> Also check for all file, since there are other issues relating to this.
>>
>>> +   2. When hash entry is found in needle , the hash index is initialized to 1
>>> +   3. The string is scanned until end and for every character, its corresponding
>>> +      hash index is compared.
>>> +   4. initial length of string (count) until first hit of accept needle to be found
>>> +      is set to 0
>>> +   4. If hash index is set to 1 for the index of string, count is returned.
>>> +   5. Otherwise count is incremented and scanning continues until end of string.  */
>>> +
>>> +#include <sysdep.h>
>>> +
>>> +#undef strspn
>>> +
>>> +    .machine  power7
>>> +EALIGN(strspn, 4, 0)
>>> +    CALL_MCOUNT 2
>>> +
>>> +    lbz r10, 0(r4)        /* load r10 with needle (r4)  */
>>> +    addi r9, r1, -256    /* r9 is a hash of 256 bytes  */
>>> +
>>> +    li r5, 16        /* set r5 = 16 as offset  */
>>> +    li r6, 32        /* set r6 = 32 as offset  */
>>> +    li r8, 48        /* set r8 = 48 as offset  */
>>> +
>>> +/*Iniatliaze hash table with Zeroes in double indexed quadword accesses  */
>>> +    xxlxor v0, v0, v0    /* prepare for initializing hash  */
>>> +
>>> +    stxvd2x v0, r0, r9    /* initialize 1st quadword  */
>>> +    stxvd2x v0, r9, r5
>>> +    stxvd2x v0, r9, r6
>>> +    stxvd2x v0, r9, r8    /* initialize 4th quadword  */
>>> +
>>> +    addi r11, r9, 64    /* r11 is index to hash  */
>>> +
>>> +    stxvd2x v0, r0, r11    /* initialize 5th quadword  */
>>> +    stxvd2x v0, r11, r5
>>> +    stxvd2x v0, r11, r6
>>> +    stxvd2x v0, r11, r8    /* initialize 8th quadword  */
>>> +
>>> +    addi r11, r9, 128    /* r11 is index to hash  */
>>> +
>>> +    stxvd2x v0, r0, r11    /* initialize 9th quadword  */
>>> +    stxvd2x v0, r11, r5
>>> +    stxvd2x v0, r11, r6
>>> +    stxvd2x v0, r11, r8    /* initialize 12th quadword  */
>>> +
>>> +    addi r11, r9, 192    /* r11 is index to hash  */
>>> +
>>> +    stxvd2x v0, r0, r11    /* initialize 13th quadword  */
>>> +    stxvd2x v0, r11, r5
>>> +    stxvd2x v0, r11, r6
>>> +    stxvd2x v0, r11, r8    /* initialize 16th quadword  */
>>> +
>>> +    li r8, 1        /* r8=1, marker into hash if found in needle  */
>>> +
>>> +    cmpdi cr7, r10, 0    /* accept needle is NULL  */
>>> +    beq cr7, L(skipHashing)    /* if needle is NULL, skip hashing  */
>>> +
>>> +    .p2align 4        /* align section to 16 byte boundary  */
>>> +L(hashing):
>>> +    stbx r8, r9, r10    /* update hash with marker for the pivot of the needle  */
>>> +    lbzu r10, 1(r4)        /* load needle into r10 and update to next  */
>>> +    cmpdi cr7, r10, 0    /* if needle is has reached NULL, continue  */
>>> +    bne cr7, L(hashing)    /* loop to hash the needle  */
>>> +
>>> +L(skipHashing):
>>> +    li r10, 0        /* load counter = 0  */
>>> +    b L(beginScan)
>>> +
>>> +    .p2align 4        /* align section to 16 byte boundary  */
>>> +L(scanUnroll):
>>> +    lbzx r8, r9, r8        /* load r8 with hash value at index  */
>>> +    cmpwi cr7, r8, 0    /* if we hit marker in hash, we have found accept needle  */
>>> +    beq cr7, L(ret1stIndex)    /* we have hit accept needle, return the count  */
>>> +
>>> +    lbz r8, 1(r3)        /* load string[1] into r8  */
>>> +    addi r10, r10, 4    /* increment counter  */
>>> +    lbzx r8, r9, r8        /* load r8 with hash value at index  */
>>> +    cmpwi cr7, r8, 0    /* if we hit marker in hash, we have found accept needle  */
>>> +    beq cr7, L(ret2ndIndex)    /* we have hit accept needle, return the count  */
>>> +
>>> +    lbz r8, 2(r3)        /* load string[2] into r8  */
>>> +    lbzx r8, r9, r8        /* load r8 with hash value at index  */
>>> +    cmpwi cr7, r8, 0    /* if we hit marker in hash, we have found accept needle  */
>>> +    beq cr7, L(ret3rdIndex)    /* we have hit accept needle, return the count  */
>>> +
>>> +    lbz r8, 3(r3)        /* load string[3] into r8  */
>>> +    lbzx r8, r9, r8        /* load r8 with hash value at index  */
>>> +    addi r3, r3, 4        /* unroll factor , increment string by 4  */
>>> +    cmpwi cr7, r8, 0    /* if we hit marker in hash, we have found accept needle  */
>>> +    beq cr7,L(ret4thIndex)    /* we have hit accept needle, return the count  */
>>> +
>>> +L(beginScan):
>>> +    lbz r8, 0(r3)        /* load string[0] into r8  */
>>> +    addi r6, r10, 1        /* place holder for counter + 1  */
>>> +    addi r5, r10, 2        /* place holder for counter + 2  */
>>> +    addi r4, r10, 3        /* place holder for counter + 3  */
>>> +    cmpdi cr7, r8, 0    /* if we hit marker in hash, we have found accept needle  */
>>> +    bne cr7, L(scanUnroll)    /* continue scanning  */
>>> +
>>> +L(ret1stIndex):
>>> +    mr r3, r10        /* update r3 for return  */
>>> +    blr            /* return  */
>>> +
>>> +L(ret2ndIndex):
>>> +    mr r3, r6        /* update r3 for return  */
>>> +    blr            /* return  */
>>> +
>>> +L(ret3rdIndex):
>>> +    mr r3, r5        /* update r3 for return  */
>>> +    blr            /* return  */
>>> +
>>> +L(ret4thIndex):
>>> +    mr r3, r4        /* update r3 for return  */
>>> +    blr            /* done  */
>>> +
>>> +END(strspn)
>>> +libc_hidden_builtin_def (strspn)
>