71ae86478e
This patch adds an optimized memset implementation for POWER8. For sizes from 0 to 255 bytes, a word/doubleword algorithm similar to POWER7 optimized one is used. For size higher than 255 two strategies are used: 1. If the constant is different than 0, the memory is written with altivec vector instruction; 2. If constant is 0, dbcz instructions are used. The loop is unrolled to clear 512 byte at time. Using vector instructions increases throughput considerable, with a double performance for sizes larger than 1024. The dcbz loops unrolls also shows performance improvement, by doubling throughput for sizes larger than 8192 bytes.
54 lines
2.0 KiB
C
54 lines
2.0 KiB
C
/* Multiple versions of memset.
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Copyright (C) 2013-2014 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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/* Define multiple versions only for definition in libc. */
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#if defined SHARED && !defined NOT_IN_libc
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/* Redefine memset so that the compiler won't complain about the type
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mismatch with the IFUNC selector in strong_alias, below. */
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# undef memset
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# define memset __redirect_memset
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# include <string.h>
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# include <shlib-compat.h>
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# include "init-arch.h"
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extern __typeof (__redirect_memset) __libc_memset;
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extern __typeof (__redirect_memset) __memset_ppc attribute_hidden;
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extern __typeof (__redirect_memset) __memset_power4 attribute_hidden;
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extern __typeof (__redirect_memset) __memset_power6 attribute_hidden;
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extern __typeof (__redirect_memset) __memset_power7 attribute_hidden;
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extern __typeof (__redirect_memset) __memset_power8 attribute_hidden;
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/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
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ifunc symbol properly. */
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libc_ifunc (__libc_memset,
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(hwcap2 & PPC_FEATURE2_ARCH_2_07)
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? __memset_power8 :
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(hwcap & PPC_FEATURE_HAS_VSX)
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? __memset_power7 :
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(hwcap & PPC_FEATURE_ARCH_2_05)
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? __memset_power6 :
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(hwcap & PPC_FEATURE_POWER4)
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? __memset_power4
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: __memset_ppc);
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#undef memset
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strong_alias (__libc_memset, memset);
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libc_hidden_ver (__libc_memset, memset);
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#endif
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