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5c74e47cd6
In this patch we take advantage of HSW memory bandwidth, manage to reduce miss branch prediction by avoiding using branch instructions and force destination to be aligned with avx & avx2 instruction. The CPU2006 403.gcc benchmark indicates this patch improves performance from 26% to 59%. * sysdeps/x86_64/multiarch/Makefile: Add memset-avx2. * sysdeps/x86_64/multiarch/memset-avx2.S: New file. * sysdeps/x86_64/multiarch/memset.S: Likewise. * sysdeps/x86_64/multiarch/memset_chk.S: Likewise. * sysdeps/x86_64/multiarch/rtld-memset.S: Likewise.
60 lines
1.8 KiB
ArmAsm
60 lines
1.8 KiB
ArmAsm
/* Multiple versions of memset
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <shlib-compat.h>
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#include <init-arch.h>
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/* Define multiple versions only for the definition in lib. */
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#ifndef NOT_IN_libc
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ENTRY(memset)
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.type memset, @gnu_indirect_function
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cmpl $0, __cpu_features+KIND_OFFSET(%rip)
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jne 1f
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call __init_cpu_features
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1: leaq __memset_sse2(%rip), %rax
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testl $bit_AVX2_Usable, __cpu_features+FEATURE_OFFSET+index_AVX2_Usable(%rip)
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jz 2f
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leaq __memset_avx2(%rip), %rax
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2: ret
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END(memset)
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#endif
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#if !defined NOT_IN_libc
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# undef memset
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# define memset __memset_sse2
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# undef __memset_chk
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# define __memset_chk __memset_chk_sse2
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# ifdef SHARED
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# undef libc_hidden_builtin_def
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/* It doesn't make sense to send libc-internal memset calls through a PLT.
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The speedup we get from using GPR instruction is likely eaten away
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by the indirect call in the PLT. */
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# define libc_hidden_builtin_def(name) \
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.globl __GI_memset; __GI_memset = __memset_sse2
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# endif
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# undef strong_alias
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# define strong_alias(original, alias)
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#endif
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#include "../memset.S"
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