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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.
45 lines
1.6 KiB
ArmAsm
45 lines
1.6 KiB
ArmAsm
/* Multiple versions of memset_chk
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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 <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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# ifdef SHARED
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ENTRY(__memset_chk)
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.type __memset_chk, @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_chk_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_chk_avx2(%rip), %rax
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2: ret
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END(__memset_chk)
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strong_alias (__memset_chk, __memset_zero_constant_len_parameter)
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.section .gnu.warning.__memset_zero_constant_len_parameter
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.string "memset used with constant zero length parameter; this could be due to transposed parameters"
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# else
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# include "../memset_chk.S"
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# endif
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#endif
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