powerpc: Optimized strncat for POWER8
Commit Message
With new optimized strnlen for POWER8 [1], this patch adds
strncat for power8 to make use of optimized strlen and strnlen.
This is faster than POWER7 current implementation for larger strings.
Tested on powerpc64 and powerpc64le.
[1] https://sourceware.org/ml/libc-alpha/2017-03/msg00491.html
--
2017-04-10 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
* sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add
strncat-power8.
* sysdeps/powerpc/powerpc64/multiarch/strncat.c (strncat): Add
__strncat_power8 to ifunc list.
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
(strncat): Add __strncat_power8 to list of strncat functions.
* sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c: New file.
---
sysdeps/powerpc/powerpc64/multiarch/Makefile | 3 ++-
.../powerpc/powerpc64/multiarch/ifunc-impl-list.c | 3 +++
.../powerpc/powerpc64/multiarch/strncat-power8.c | 31 ++++++++++++++++++++++
sysdeps/powerpc/powerpc64/multiarch/strncat.c | 5 +++-
4 files changed, 40 insertions(+), 2 deletions(-)
create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c
Comments
Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> writes:
> With new optimized strnlen for POWER8 [1], this patch adds
> strncat for power8 to make use of optimized strlen and strnlen.
> This is faster than POWER7 current implementation for larger strings.
>
> Tested on powerpc64 and powerpc64le.
>
> [1] https://sourceware.org/ml/libc-alpha/2017-03/msg00491.html
>
> --
> 2017-04-10 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
>
> * sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add
> strncat-power8.
> * sysdeps/powerpc/powerpc64/multiarch/strncat.c (strncat): Add
> __strncat_power8 to ifunc list.
> * sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
> (strncat): Add __strncat_power8 to list of strncat functions.
> * sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c: New file.
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> index 38233a7..0eb3d07 100644
> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> @@ -15,7 +15,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
> strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
> strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
> stpcpy-power7 stpcpy-ppc64 \
> - strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
> + strrchr-power7 strrchr-ppc64 \
> + strncat-power8 strncat-power7 strncat-ppc64 \
I wonder if these C optimizations should be forced to build using -mcpu and
-mtune. At least for those processors supported by the minimum required GCC
version.
Anyway, it shouldn't affect your patch as -mcpu=power8 isn't available on
GCC 4.7
LGTM.
On 4/10/17, 4:59 AM, "Rajalakshmi Srinivasaraghavan" <libc-alpha-owner@sourceware.org on behalf of raji@linux.vnet.ibm.com> wrote:
With new optimized strnlen for POWER8 [1], this patch adds
strncat for power8 to make use of optimized strlen and strnlen.
This is faster than POWER7 current implementation for larger strings.
Tested on powerpc64 and powerpc64le.
OK.
@@ -15,7 +15,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
stpcpy-power7 stpcpy-ppc64 \
- strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
+ strrchr-power7 strrchr-ppc64 \
+ strncat-power8 strncat-power7 strncat-ppc64 \
strncpy-power7 strncpy-ppc64 \
stpncpy-power8 stpncpy-power7 stpncpy-ppc64 \
strcmp-power9 strcmp-power8 strcmp-power7 strcmp-ppc64 \
@@ -292,6 +292,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/powerpc/powerpc64/multiarch/strncat.c. */
IFUNC_IMPL (i, name, strncat,
IFUNC_IMPL_ADD (array, i, strncat,
+ hwcap2 & PPC_FEATURE2_ARCH_2_07,
+ __strncat_power8)
+ IFUNC_IMPL_ADD (array, i, strncat,
hwcap & PPC_FEATURE_HAS_VSX,
__strncat_power7)
IFUNC_IMPL_ADD (array, i, strncat, 1,
new file mode 100644
@@ -0,0 +1,31 @@
+/* Copyright (C) 2017 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 STRNCAT __strncat_power8
+
+extern __typeof (strncat) __strncat_power8 attribute_hidden;
+extern __typeof (strlen) __strlen_power8 attribute_hidden;
+extern __typeof (strnlen) __strnlen_power8 attribute_hidden;
+extern __typeof (memcpy) __memcpy_power7 attribute_hidden;
+
+#define strlen __strlen_power8
+#define __strnlen __strnlen_power8
+#define memcpy __memcpy_power7
+
+#include <string/strncat.c>
@@ -23,9 +23,12 @@
extern __typeof (strncat) __strncat_ppc attribute_hidden;
extern __typeof (strncat) __strncat_power7 attribute_hidden;
+extern __typeof (strncat) __strncat_power8 attribute_hidden;
libc_ifunc (strncat,
- (hwcap & PPC_FEATURE_HAS_VSX)
+ (hwcap & PPC_FEATURE2_ARCH_2_07)
+ ? __strncat_power8
+ : (hwcap & PPC_FEATURE_HAS_VSX)
? __strncat_power7
: __strncat_ppc);
#endif