PowerPC: strspn optimization for PPC64/POWER7

The optimization is achieved by following techniques:
  > hashing of needle.
  > hashing avoids scanning of duplicate entries in needle across the string.
  > initializing the hash table with Vector instructions (VSX) by quadword access.
  > unrolling when scanning for character in string across hash table.
This commit is contained in:
Vidya Ranganathan 2014-03-10 12:20:36 -04:00 committed by Adhemerval Zanella
parent ba9cc0714e
commit e65caf1f1d
8 changed files with 296 additions and 4 deletions

View File

@ -1,3 +1,16 @@
2014-03-11 Vidya Ranganathan <vidya@linux.vnet.ibm.com>
* sysdeps/powerpc/powerpc64/power7/strspn.S: New file: Optimization.
* sysdeps/powerpc/powerpc64/multiarch/strspn.c: New file:
multiarch strspn for PPC64.
* sysdeps/powerpc/powerpc64/multiarch/strspn-ppc64.c: New file
* sysdeps/powerpc/powerpc64/multiarch/strspn-power7.S: New file
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c:
(__libc_ifunc_impl_list): Likewise.
* sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strspn
multiarch optimizations
* string/strspn.c (strspn): Using macro to redefine symbol name.
2014-03-10 Vidya Ranganathan <vidya@linux.vnet.ibm.com> 2014-03-10 Vidya Ranganathan <vidya@linux.vnet.ibm.com>
Adhemerval Zanella <azanella@linux.vnet.ibm.com> Adhemerval Zanella <azanella@linux.vnet.ibm.com>

View File

@ -18,13 +18,14 @@
#include <string.h> #include <string.h>
#undef strspn #undef strspn
#ifndef STRSPN
#define STRSPN strspn
#endif
/* Return the length of the maximum initial segment /* Return the length of the maximum initial segment
of S which contains only characters in ACCEPT. */ of S which contains only characters in ACCEPT. */
size_t size_t
strspn (s, accept) STRSPN (const char *s, const char *accept)
const char *s;
const char *accept;
{ {
const char *p; const char *p;
const char *a; const char *a;

View File

@ -14,7 +14,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
wcsrchr-ppc64 wcscpy-power7 wcscpy-power6 wcscpy-ppc64 \ wcsrchr-ppc64 wcscpy-power7 wcscpy-power6 wcscpy-ppc64 \
wordcopy-power7 wordcopy-power6 wordcopy-ppc64 \ wordcopy-power7 wordcopy-power6 wordcopy-ppc64 \
strcpy-power7 strcpy-ppc64 stpcpy-power7 stpcpy-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-power7.c += -mcpu=power7 -funroll-loops
CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops

View File

@ -254,5 +254,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL_ADD (array, i, strncat, 1, IFUNC_IMPL_ADD (array, i, strncat, 1,
__strncat_ppc)) __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; return i;
} }

View File

@ -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>

View File

@ -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>

View File

@ -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

View File

@ -0,0 +1,165 @@
/* 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
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)