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05f3633da4
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 instruction. The CPU2006 403.gcc benchmark indicates this patch improves performance from 2% to 10%.
81 lines
2.7 KiB
ArmAsm
81 lines
2.7 KiB
ArmAsm
/* Multiple versions of mempcpy
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2010-2014 Free Software Foundation, Inc.
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Contributed by Intel Corporation.
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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 and for
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DSO. In static binaries we need mempcpy before the initialization
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happened. */
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#if defined SHARED && !defined NOT_IN_libc
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ENTRY(__mempcpy)
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.type __mempcpy, @gnu_indirect_function
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cmpl $0, KIND_OFFSET+__cpu_features(%rip)
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jne 1f
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call __init_cpu_features
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1: leaq __mempcpy_sse2(%rip), %rax
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testl $bit_SSSE3, __cpu_features+CPUID_OFFSET+index_SSSE3(%rip)
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jz 2f
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leaq __mempcpy_ssse3(%rip), %rax
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testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
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jz 2f
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leaq __mempcpy_ssse3_back(%rip), %rax
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testl $bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
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jz 2f
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leaq __mempcpy_avx_unaligned(%rip), %rax
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2: ret
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END(__mempcpy)
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# undef ENTRY
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# define ENTRY(name) \
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.type __mempcpy_sse2, @function; \
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.p2align 4; \
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.globl __mempcpy_sse2; \
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.hidden __mempcpy_sse2; \
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__mempcpy_sse2: cfi_startproc; \
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CALL_MCOUNT
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# undef END
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# define END(name) \
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cfi_endproc; .size __mempcpy_sse2, .-__mempcpy_sse2
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# undef ENTRY_CHK
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# define ENTRY_CHK(name) \
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.type __mempcpy_chk_sse2, @function; \
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.globl __mempcpy_chk_sse2; \
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.p2align 4; \
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__mempcpy_chk_sse2: cfi_startproc; \
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CALL_MCOUNT
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# undef END_CHK
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# define END_CHK(name) \
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cfi_endproc; .size __mempcpy_chk_sse2, .-__mempcpy_chk_sse2
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# undef libc_hidden_def
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# undef libc_hidden_builtin_def
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/* It doesn't make sense to send libc-internal mempcpy calls through a PLT.
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The speedup we get from using SSSE3 instruction is likely eaten away
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by the indirect call in the PLT. */
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# define libc_hidden_def(name) \
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.globl __GI_mempcpy; __GI_mempcpy = __mempcpy_sse2
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# define libc_hidden_builtin_def(name) \
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.globl __GI___mempcpy; __GI___mempcpy = __mempcpy_sse2
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#endif
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#include "../mempcpy.S"
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