[PATCH v1] x86: Remove generic strncat, strncpy, and stpncpy implementations
H.J. Lu
hjl.tools@gmail.com
Wed Jul 6 01:32:28 GMT 2022
On Tue, Jul 5, 2022 at 5:06 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> These functions all have optimized versions:
> __strncat_sse2_unaligned, __strncpy_sse2_unaligned, and
> stpncpy_sse2_unaligned which are faster than their respective generic
> implementations. Since the sse2 versions can run on baseline x86_64,
Is this true on all x86-64 processors?
> we should use these as the baseline implementation and can remove the
> generic implementations.
>
> Geometric mean of N=20 runs of the entire benchmark suite on:
> 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz (Tigerlake)
>
> __strncat_sse2_unaligned / __strncat_generic: .944
> __strncpy_sse2_unaligned / __strncpy_generic: .726
> __stpncpy_sse2_unaligned / __stpncpy_generic: .650
>
> Tested build with and without multiarch and full check with multiarch.
> ---
> sysdeps/x86_64/multiarch/Makefile | 3 --
> sysdeps/x86_64/multiarch/ifunc-impl-list.c | 9 ++--
> sysdeps/x86_64/multiarch/ifunc-strcpy.h | 8 +---
> sysdeps/x86_64/multiarch/ifunc-strncpy.h | 48 ++++++++++++++++++++++
> sysdeps/x86_64/multiarch/stpncpy-generic.c | 26 ------------
> sysdeps/x86_64/multiarch/stpncpy.c | 3 +-
> sysdeps/x86_64/multiarch/strncat-generic.c | 21 ----------
> sysdeps/x86_64/multiarch/strncat.c | 3 +-
> sysdeps/x86_64/multiarch/strncpy-generic.c | 24 -----------
> sysdeps/x86_64/multiarch/strncpy.c | 3 +-
> 10 files changed, 56 insertions(+), 92 deletions(-)
> create mode 100644 sysdeps/x86_64/multiarch/ifunc-strncpy.h
> delete mode 100644 sysdeps/x86_64/multiarch/stpncpy-generic.c
> delete mode 100644 sysdeps/x86_64/multiarch/strncat-generic.c
> delete mode 100644 sysdeps/x86_64/multiarch/strncpy-generic.c
>
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index 18cea04423..04e238efa0 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -45,7 +45,6 @@ sysdep_routines += \
> stpcpy-sse2-unaligned \
> stpncpy-avx2 \
> stpncpy-avx2-rtm \
> - stpncpy-generic \
> stpncpy-evex \
> stpncpy-sse2-unaligned \
> strcasecmp_l-avx2 \
> @@ -92,7 +91,6 @@ sysdep_routines += \
> strncase_l-sse4_2 \
> strncat-avx2 \
> strncat-avx2-rtm \
> - strncat-generic \
> strncat-evex \
> strncat-sse2-unaligned \
> strncmp-avx2 \
> @@ -102,7 +100,6 @@ sysdep_routines += \
> strncmp-sse4_2 \
> strncpy-avx2 \
> strncpy-avx2-rtm \
> - strncpy-generic \
> strncpy-evex \
> strncpy-sse2-unaligned \
> strnlen-avx2 \
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index adf7d4bafd..2c96cb62d2 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -403,8 +403,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> && CPU_FEATURE_USABLE (AVX512BW)),
> __stpncpy_evex)
> IFUNC_IMPL_ADD (array, i, stpncpy, 1,
> - __stpncpy_sse2_unaligned)
> - IFUNC_IMPL_ADD (array, i, stpncpy, 1, __stpncpy_generic))
> + __stpncpy_sse2_unaligned))
>
> /* Support sysdeps/x86_64/multiarch/stpcpy.c. */
> IFUNC_IMPL (i, name, stpcpy,
> @@ -618,8 +617,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> && CPU_FEATURE_USABLE (AVX512BW)),
> __strncat_evex)
> IFUNC_IMPL_ADD (array, i, strncat, 1,
> - __strncat_sse2_unaligned)
> - IFUNC_IMPL_ADD (array, i, strncat, 1, __strncat_generic))
> + __strncat_sse2_unaligned))
>
> /* Support sysdeps/x86_64/multiarch/strncpy.c. */
> IFUNC_IMPL (i, name, strncpy,
> @@ -634,8 +632,7 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> && CPU_FEATURE_USABLE (AVX512BW)),
> __strncpy_evex)
> IFUNC_IMPL_ADD (array, i, strncpy, 1,
> - __strncpy_sse2_unaligned)
> - IFUNC_IMPL_ADD (array, i, strncpy, 1, __strncpy_generic))
> + __strncpy_sse2_unaligned))
>
> /* Support sysdeps/x86_64/multiarch/strpbrk.c. */
> IFUNC_IMPL (i, name, strpbrk,
> diff --git a/sysdeps/x86_64/multiarch/ifunc-strcpy.h b/sysdeps/x86_64/multiarch/ifunc-strcpy.h
> index 80529458d1..a15afa44e9 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-strcpy.h
> +++ b/sysdeps/x86_64/multiarch/ifunc-strcpy.h
> @@ -20,11 +20,7 @@
>
> #include <init-arch.h>
>
> -#ifndef GENERIC
> -# define GENERIC sse2
> -#endif
> -
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (GENERIC) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned)
> attribute_hidden;
> extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
> @@ -53,5 +49,5 @@ IFUNC_SELECTOR (void)
> if (CPU_FEATURES_ARCH_P (cpu_features, Fast_Unaligned_Load))
> return OPTIMIZE (sse2_unaligned);
>
> - return OPTIMIZE (GENERIC);
> + return OPTIMIZE (sse2);
> }
> diff --git a/sysdeps/x86_64/multiarch/ifunc-strncpy.h b/sysdeps/x86_64/multiarch/ifunc-strncpy.h
> new file mode 100644
> index 0000000000..323225af4d
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/ifunc-strncpy.h
> @@ -0,0 +1,48 @@
> +/* Common definition for ifunc st{r|p}n{cpy|cat}
> + All versions must be listed in ifunc-impl-list.c.
> + Copyright (C) 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 <init-arch.h>
> +
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned)
> + attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
> +
> +static inline void *
> +IFUNC_SELECTOR (void)
> +{
> + const struct cpu_features* cpu_features = __get_cpu_features ();
> +
> + if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> + && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
> + {
> + if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> + && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
> + return OPTIMIZE (evex);
> +
> + if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> + return OPTIMIZE (avx2_rtm);
> +
> + if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> + return OPTIMIZE (avx2);
> + }
> +
> + return OPTIMIZE (sse2_unaligned);
> +}
> diff --git a/sysdeps/x86_64/multiarch/stpncpy-generic.c b/sysdeps/x86_64/multiarch/stpncpy-generic.c
> deleted file mode 100644
> index 87826845b0..0000000000
> --- a/sysdeps/x86_64/multiarch/stpncpy-generic.c
> +++ /dev/null
> @@ -1,26 +0,0 @@
> -/* stpncpy.
> - Copyright (C) 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/>. */
> -
> -
> -#define STPNCPY __stpncpy_generic
> -#undef weak_alias
> -#define weak_alias(ignored1, ignored2)
> -#undef libc_hidden_def
> -#define libc_hidden_def(stpncpy)
> -
> -#include <string/stpncpy.c>
> diff --git a/sysdeps/x86_64/multiarch/stpncpy.c b/sysdeps/x86_64/multiarch/stpncpy.c
> index 879bc83f0b..a8d083ff0d 100644
> --- a/sysdeps/x86_64/multiarch/stpncpy.c
> +++ b/sysdeps/x86_64/multiarch/stpncpy.c
> @@ -25,9 +25,8 @@
> # undef stpncpy
> # undef __stpncpy
>
> -# define GENERIC generic
> # define SYMBOL_NAME stpncpy
> -# include "ifunc-strcpy.h"
> +# include "ifunc-strncpy.h"
>
> libc_ifunc_redirected (__redirect_stpncpy, __stpncpy, IFUNC_SELECTOR ());
>
> diff --git a/sysdeps/x86_64/multiarch/strncat-generic.c b/sysdeps/x86_64/multiarch/strncat-generic.c
> deleted file mode 100644
> index 0090669cd1..0000000000
> --- a/sysdeps/x86_64/multiarch/strncat-generic.c
> +++ /dev/null
> @@ -1,21 +0,0 @@
> -/* strncat.
> - Copyright (C) 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/>. */
> -
> -
> -#define STRNCAT __strncat_generic
> -#include <string/strncat.c>
> diff --git a/sysdeps/x86_64/multiarch/strncat.c b/sysdeps/x86_64/multiarch/strncat.c
> index 50fba8a41f..a590c25d51 100644
> --- a/sysdeps/x86_64/multiarch/strncat.c
> +++ b/sysdeps/x86_64/multiarch/strncat.c
> @@ -24,8 +24,7 @@
> # undef strncat
>
> # define SYMBOL_NAME strncat
> -# define GENERIC generic
> -# include "ifunc-strcpy.h"
> +# include "ifunc-strncpy.h"
>
> libc_ifunc_redirected (__redirect_strncat, strncat, IFUNC_SELECTOR ());
> strong_alias (strncat, __strncat);
> diff --git a/sysdeps/x86_64/multiarch/strncpy-generic.c b/sysdeps/x86_64/multiarch/strncpy-generic.c
> deleted file mode 100644
> index 9916153dd5..0000000000
> --- a/sysdeps/x86_64/multiarch/strncpy-generic.c
> +++ /dev/null
> @@ -1,24 +0,0 @@
> -/* strncpy.
> - Copyright (C) 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/>. */
> -
> -
> -#define STRNCPY __strncpy_generic
> -#undef libc_hidden_builtin_def
> -#define libc_hidden_builtin_def(strncpy)
> -
> -#include <string/strncpy.c>
> diff --git a/sysdeps/x86_64/multiarch/strncpy.c b/sysdeps/x86_64/multiarch/strncpy.c
> index 7fc7d72ec5..c83440f0e3 100644
> --- a/sysdeps/x86_64/multiarch/strncpy.c
> +++ b/sysdeps/x86_64/multiarch/strncpy.c
> @@ -24,8 +24,7 @@
> # undef strncpy
>
> # define SYMBOL_NAME strncpy
> -# define GENERIC generic
> -# include "ifunc-strcpy.h"
> +# include "ifunc-strncpy.h"
>
> libc_ifunc_redirected (__redirect_strncpy, strncpy, IFUNC_SELECTOR ());
>
> --
> 2.34.1
>
--
H.J.
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