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Re: [PATCH] Remove Prefer_SSE_for_memop on x64
- From: Dmitrieva Liubov <liubov dot dmitrieva at gmail dot com>
- To: Ondřej Bílka <neleai at seznam dot cz>
- Cc: libc-alpha at sourceware dot org
- Date: Fri, 15 Feb 2013 12:24:05 +0400
- Subject: Re: [PATCH] Remove Prefer_SSE_for_memop on x64
- References: <20130214213001.GA11656@domone.kolej.mff.cuni.cz>
Looks good to me.
But I would add a sentence more after "Update" in the Change Log
entries to clarify what is the update about...
--
Liubov Dmitrieva
Intel Corporation
2013/2/15 OndÅej BÃlka <neleai@seznam.cz>:
> Hello,
> As I asked in
> http://www.sourceware.org/ml/libc-alpha/2013-02/msg00203.html
> nobody objected to keep non-sse memset on x64.
>
> This patch removes that implementation and flag Prefer_SSE_for_memop
> which is always set and only choose sse memset over nonsse one.
>
> 2013-02-14 OndÅej BÃlka <neleai@seznam.cz>
>
> * sysdeps/x86_64/memset.S: Always define bcopy.
> * sysdeps/x86_64/multiarch/Makefile: Update.
> * sysdeps/x86_64/multiarch/ifunc-impl-list.c: Update.
> * sysdeps/x86_64/multiarch/init-arch.c: Remove Prefer_SSE_for_memop.
> * sysdeps/x86_64/multiarch/init-arch.h: Likewise.
> * sysdeps/x86_64/multiarch/bzero.S: Remove.
> * sysdeps/x86_64/multiarch/memset-x86-64.S: Likewise.
> * sysdeps/x86_64/multiarch/memset.S: Likewise.
> * sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
>
> ---
> sysdeps/x86_64/memset.S | 2 +-
> sysdeps/x86_64/multiarch/Makefile | 2 +-
> sysdeps/x86_64/multiarch/bzero.S | 28 ----------
> sysdeps/x86_64/multiarch/ifunc-impl-list.c | 11 ----
> sysdeps/x86_64/multiarch/init-arch.c | 11 ----
> sysdeps/x86_64/multiarch/init-arch.h | 4 --
> sysdeps/x86_64/multiarch/memset-x86-64.S | 19 -------
> sysdeps/x86_64/multiarch/memset.S | 79 ----------------------------
> sysdeps/x86_64/multiarch/memset_chk.S | 44 ---------------
> 9 files changed, 2 insertions(+), 198 deletions(-)
> delete mode 100644 sysdeps/x86_64/multiarch/bzero.S
> delete mode 100644 sysdeps/x86_64/multiarch/memset-x86-64.S
> delete mode 100644 sysdeps/x86_64/multiarch/memset.S
> delete mode 100644 sysdeps/x86_64/multiarch/memset_chk.S
>
> diff --git a/sysdeps/x86_64/memset.S b/sysdeps/x86_64/memset.S
> index f3a4d44..b393efe 100644
> --- a/sysdeps/x86_64/memset.S
> +++ b/sysdeps/x86_64/memset.S
> @@ -23,7 +23,7 @@
> #define __STOS_UPPER_BOUNDARY $65536
>
> .text
> -#if !defined NOT_IN_libc && !defined USE_MULTIARCH
> +#if !defined NOT_IN_libc
> ENTRY(__bzero)
> mov %rsi,%rdx /* Adjust parameter. */
> xorl %esi,%esi /* Fill with 0s. */
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index dd6c27d..4f7c070 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -10,7 +10,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3 \
> strend-sse4 memcmp-sse4 memcpy-ssse3 mempcpy-ssse3 \
> memmove-ssse3 memcpy-ssse3-back mempcpy-ssse3-back \
> memmove-ssse3-back strcasestr-nonascii strcasecmp_l-ssse3 \
> - strncase_l-ssse3 strlen-sse4 strlen-sse2-no-bsf memset-x86-64 \
> + strncase_l-ssse3 strlen-sse4 strlen-sse2-no-bsf \
> strcpy-ssse3 strncpy-ssse3 stpcpy-ssse3 stpncpy-ssse3 \
> strcpy-sse2-unaligned strncpy-sse2-unaligned \
> stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
> diff --git a/sysdeps/x86_64/multiarch/bzero.S b/sysdeps/x86_64/multiarch/bzero.S
> deleted file mode 100644
> index 88e96ea..0000000
> --- a/sysdeps/x86_64/multiarch/bzero.S
> +++ /dev/null
> @@ -1,28 +0,0 @@
> -/* bzero. x86-64 version.
> - Copyright (C) 2010-2013 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>
> -#include <init-arch.h>
> -
> - .text
> -ENTRY(__bzero)
> - mov %rsi,%rdx /* Adjust parameter. */
> - xorl %esi,%esi /* Fill with 0s. */
> - jmp __libc_memset /* Branch to IFUNC memset. */
> -END(__bzero)
> -weak_alias (__bzero, bzero)
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index 643cb2d..cb4aba3 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -61,17 +61,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> __memmove_ssse3)
> IFUNC_IMPL_ADD (array, i, memmove, 1, __memmove_sse2))
>
> - /* Support sysdeps/x86_64/multiarch/memset_chk.S. */
> - IFUNC_IMPL (i, name, __memset_chk,
> - IFUNC_IMPL_ADD (array, i, __memset_chk, 1, __memset_chk_sse2)
> - IFUNC_IMPL_ADD (array, i, __memset_chk, 1,
> - __memset_chk_x86_64))
> -
> - /* Support sysdeps/x86_64/multiarch/memset.S. */
> - IFUNC_IMPL (i, name, memset,
> - IFUNC_IMPL_ADD (array, i, memset, 1, __memset_sse2)
> - IFUNC_IMPL_ADD (array, i, memset, 1, __memset_x86_64))
> -
> /* Support sysdeps/x86_64/multiarch/rawmemchr.S. */
> IFUNC_IMPL (i, name, rawmemchr,
> IFUNC_IMPL_ADD (array, i, rawmemchr, HAS_SSE4_2,
> diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
> index 992cbfb..7daaf46 100644
> --- a/sysdeps/x86_64/multiarch/init-arch.c
> +++ b/sysdeps/x86_64/multiarch/init-arch.c
> @@ -58,11 +58,6 @@ __init_cpu_features (void)
>
> get_common_indeces (&family, &model);
>
> - /* Intel processors prefer SSE instruction for memory/string
> - routines if they are available. */
> - __cpu_features.feature[index_Prefer_SSE_for_memop]
> - |= bit_Prefer_SSE_for_memop;
> -
> unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
> unsigned int extended_family = (eax >> 20) & 0xff;
> unsigned int extended_model = (eax >> 12) & 0xf0;
> @@ -125,12 +120,6 @@ __init_cpu_features (void)
>
> ecx = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx;
>
> - /* AMD processors prefer SSE instructions for memory/string routines
> - if they are available, otherwise they prefer integer instructions. */
> - if ((ecx & 0x200))
> - __cpu_features.feature[index_Prefer_SSE_for_memop]
> - |= bit_Prefer_SSE_for_memop;
> -
> unsigned int eax;
> __cpuid (0x80000000, eax, ebx, ecx, edx);
> if (eax >= 0x80000001)
> diff --git a/sysdeps/x86_64/multiarch/init-arch.h b/sysdeps/x86_64/multiarch/init-arch.h
> index 0aece18..28edbf7 100644
> --- a/sysdeps/x86_64/multiarch/init-arch.h
> +++ b/sysdeps/x86_64/multiarch/init-arch.h
> @@ -18,7 +18,6 @@
> #define bit_Fast_Rep_String (1 << 0)
> #define bit_Fast_Copy_Backward (1 << 1)
> #define bit_Slow_BSF (1 << 2)
> -#define bit_Prefer_SSE_for_memop (1 << 3)
> #define bit_Fast_Unaligned_Load (1 << 4)
> #define bit_Prefer_PMINUB_for_stringop (1 << 5)
> #define bit_AVX_Usable (1 << 6)
> @@ -58,7 +57,6 @@
> # define index_Fast_Rep_String FEATURE_INDEX_1*FEATURE_SIZE
> # define index_Fast_Copy_Backward FEATURE_INDEX_1*FEATURE_SIZE
> # define index_Slow_BSF FEATURE_INDEX_1*FEATURE_SIZE
> -# define index_Prefer_SSE_for_memop FEATURE_INDEX_1*FEATURE_SIZE
> # define index_Fast_Unaligned_Load FEATURE_INDEX_1*FEATURE_SIZE
> # define index_Prefer_PMINUB_for_stringop FEATURE_INDEX_1*FEATURE_SIZE
> # define index_AVX_Usable FEATURE_INDEX_1*FEATURE_SIZE
> @@ -157,7 +155,6 @@ extern const struct cpu_features *__get_cpu_features (void)
> # define index_Fast_Rep_String FEATURE_INDEX_1
> # define index_Fast_Copy_Backward FEATURE_INDEX_1
> # define index_Slow_BSF FEATURE_INDEX_1
> -# define index_Prefer_SSE_for_memop FEATURE_INDEX_1
> # define index_Fast_Unaligned_Load FEATURE_INDEX_1
> # define index_AVX_Usable FEATURE_INDEX_1
> # define index_FMA_Usable FEATURE_INDEX_1
> @@ -169,7 +166,6 @@ extern const struct cpu_features *__get_cpu_features (void)
> # define HAS_FAST_REP_STRING HAS_ARCH_FEATURE (Fast_Rep_String)
> # define HAS_FAST_COPY_BACKWARD HAS_ARCH_FEATURE (Fast_Copy_Backward)
> # define HAS_SLOW_BSF HAS_ARCH_FEATURE (Slow_BSF)
> -# define HAS_PREFER_SSE_FOR_MEMOP HAS_ARCH_FEATURE (Prefer_SSE_for_memop)
> # define HAS_FAST_UNALIGNED_LOAD HAS_ARCH_FEATURE (Fast_Unaligned_Load)
> # define HAS_AVX HAS_ARCH_FEATURE (AVX_Usable)
> # define HAS_FMA HAS_ARCH_FEATURE (FMA_Usable)
> diff --git a/sysdeps/x86_64/multiarch/memset-x86-64.S b/sysdeps/x86_64/multiarch/memset-x86-64.S
> deleted file mode 100644
> index 551d105..0000000
> --- a/sysdeps/x86_64/multiarch/memset-x86-64.S
> +++ /dev/null
> @@ -1,19 +0,0 @@
> -#include <sysdep.h>
> -
> -#ifndef NOT_IN_libc
> -# undef ENTRY_CHK
> -# define ENTRY_CHK(name) \
> - .type __memset_chk_x86_64, @function; \
> - .globl __memset_chk_x86_64; \
> - .p2align 4; \
> - __memset_chk_x86_64: cfi_startproc; \
> - CALL_MCOUNT
> -# undef END_CHK
> -# define END_CHK(name) \
> - cfi_endproc; .size __memset_chk_x86_64, .-__memset_chk_x86_64
> -
> -# undef libc_hidden_builtin_def
> -# define libc_hidden_builtin_def(name)
> -# define memset __memset_x86_64
> -# include "../memset.S"
> -#endif
> diff --git a/sysdeps/x86_64/multiarch/memset.S b/sysdeps/x86_64/multiarch/memset.S
> deleted file mode 100644
> index 7f673fa..0000000
> --- a/sysdeps/x86_64/multiarch/memset.S
> +++ /dev/null
> @@ -1,79 +0,0 @@
> -/* Multiple versions of memset
> - All versions must be listed in ifunc-impl-list.c.
> - Copyright (C) 2010-2013 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>
> -#include <init-arch.h>
> -
> -/* Define multiple versions only for the definition in lib. */
> -#ifndef NOT_IN_libc
> -ENTRY(memset)
> - .type memset, @gnu_indirect_function
> - cmpl $0, __cpu_features+KIND_OFFSET(%rip)
> - jne 1f
> - call __init_cpu_features
> -1: leaq __memset_x86_64(%rip), %rax
> - testl $bit_Prefer_SSE_for_memop, __cpu_features+FEATURE_OFFSET+index_Prefer_SSE_for_memop(%rip)
> - jz 2f
> - leaq __memset_sse2(%rip), %rax
> -2: ret
> -END(memset)
> -
> -/* Define internal IFUNC memset for bzero. */
> - .globl __libc_memset
> - .hidden __libc_memset
> - __libc_memset = memset
> -
> -# define USE_SSE2 1
> -
> -# undef ENTRY
> -# define ENTRY(name) \
> - .type __memset_sse2, @function; \
> - .globl __memset_sse2; \
> - .p2align 4; \
> - __memset_sse2: cfi_startproc; \
> - CALL_MCOUNT
> -# undef END
> -# define END(name) \
> - cfi_endproc; .size __memset_sse2, .-__memset_sse2
> -
> -# undef ENTRY_CHK
> -# define ENTRY_CHK(name) \
> - .type __memset_chk_sse2, @function; \
> - .globl __memset_chk_sse2; \
> - .p2align 4; \
> - __memset_chk_sse2: cfi_startproc; \
> - CALL_MCOUNT
> -# undef END_CHK
> -# define END_CHK(name) \
> - cfi_endproc; .size __memset_chk_sse2, .-__memset_chk_sse2
> -
> -# ifdef SHARED
> -# undef libc_hidden_builtin_def
> -/* It doesn't make sense to send libc-internal memset calls through a PLT.
> - The speedup we get from using GPR instruction is likely eaten away
> - by the indirect call in the PLT. */
> -# define libc_hidden_builtin_def(name) \
> - .globl __GI_memset; __GI_memset = __memset_sse2
> -# endif
> -
> -# undef strong_alias
> -# define strong_alias(original, alias)
> -#endif
> -
> -#include "../memset.S"
> diff --git a/sysdeps/x86_64/multiarch/memset_chk.S b/sysdeps/x86_64/multiarch/memset_chk.S
> deleted file mode 100644
> index 55e2635..0000000
> --- a/sysdeps/x86_64/multiarch/memset_chk.S
> +++ /dev/null
> @@ -1,44 +0,0 @@
> -/* Multiple versions of __memset_chk
> - All versions must be listed in ifunc-impl-list.c.
> - Copyright (C) 2010-2013 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>
> -#include <init-arch.h>
> -
> -/* Define multiple versions only for the definition in lib. */
> -#ifndef NOT_IN_libc
> -# ifdef SHARED
> -ENTRY(__memset_chk)
> - .type __memset_chk, @gnu_indirect_function
> - cmpl $0, __cpu_features+KIND_OFFSET(%rip)
> - jne 1f
> - call __init_cpu_features
> -1: leaq __memset_chk_x86_64(%rip), %rax
> - testl $bit_Prefer_SSE_for_memop, __cpu_features+FEATURE_OFFSET+index_Prefer_SSE_for_memop(%rip)
> - jz 2f
> - leaq __memset_chk_sse2(%rip), %rax
> -2: ret
> -END(__memset_chk)
> -
> -strong_alias (__memset_chk, __memset_zero_constant_len_parameter)
> - .section .gnu.warning.__memset_zero_constant_len_parameter
> - .string "memset used with constant zero length parameter; this could be due to transposed parameters"
> -# else
> -# include "../memset_chk.S"
> -# endif
> -#endif
> --
> 1.7.4.4
>