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e41b395523
On AMD processors, memcpy optimized with unaligned SSE load is slower than emcpy optimized with aligned SSSE3 while other string functions are faster with unaligned SSE load. A feature bit, Fast_Unaligned_Copy, is added to select memcpy optimized with unaligned SSE load. [BZ #19583] * sysdeps/x86/cpu-features.c (init_cpu_features): Set Fast_Unaligned_Copy with Fast_Unaligned_Load for Intel processors. Set Fast_Copy_Backward for AMD Excavator processors. * sysdeps/x86/cpu-features.h (bit_arch_Fast_Unaligned_Copy): New. (index_arch_Fast_Unaligned_Copy): Likewise. * sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check Fast_Unaligned_Copy instead of Fast_Unaligned_Load.
263 lines
8.3 KiB
C
263 lines
8.3 KiB
C
/* Initialize CPU feature data.
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This file is part of the GNU C Library.
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Copyright (C) 2008-2016 Free Software Foundation, Inc.
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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 <cpuid.h>
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#include <cpu-features.h>
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static void
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get_common_indeces (struct cpu_features *cpu_features,
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unsigned int *family, unsigned int *model,
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unsigned int *extended_model)
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{
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if (family)
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{
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unsigned int eax;
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__cpuid (1, eax, cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx);
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cpu_features->cpuid[COMMON_CPUID_INDEX_1].eax = eax;
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*family = (eax >> 8) & 0x0f;
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*model = (eax >> 4) & 0x0f;
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*extended_model = (eax >> 12) & 0xf0;
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if (*family == 0x0f)
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{
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*family += (eax >> 20) & 0xff;
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*model += *extended_model;
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}
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}
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if (cpu_features->max_cpuid >= 7)
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__cpuid_count (7, 0,
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cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax,
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cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx);
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/* Can we call xgetbv? */
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if (CPU_FEATURES_CPU_P (cpu_features, OSXSAVE))
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{
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unsigned int xcrlow;
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unsigned int xcrhigh;
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asm ("xgetbv" : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0));
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/* Is YMM and XMM state usable? */
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if ((xcrlow & (bit_YMM_state | bit_XMM_state)) ==
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(bit_YMM_state | bit_XMM_state))
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{
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/* Determine if AVX is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, AVX))
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cpu_features->feature[index_arch_AVX_Usable]
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|= bit_arch_AVX_Usable;
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/* Determine if AVX2 is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, AVX2))
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cpu_features->feature[index_arch_AVX2_Usable]
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|= bit_arch_AVX2_Usable;
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/* Check if OPMASK state, upper 256-bit of ZMM0-ZMM15 and
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ZMM16-ZMM31 state are enabled. */
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if ((xcrlow & (bit_Opmask_state | bit_ZMM0_15_state
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| bit_ZMM16_31_state)) ==
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(bit_Opmask_state | bit_ZMM0_15_state | bit_ZMM16_31_state))
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{
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/* Determine if AVX512F is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, AVX512F))
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{
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cpu_features->feature[index_arch_AVX512F_Usable]
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|= bit_arch_AVX512F_Usable;
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/* Determine if AVX512DQ is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, AVX512DQ))
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cpu_features->feature[index_arch_AVX512DQ_Usable]
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|= bit_arch_AVX512DQ_Usable;
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}
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}
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/* Determine if FMA is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, FMA))
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cpu_features->feature[index_arch_FMA_Usable]
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|= bit_arch_FMA_Usable;
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/* Determine if FMA4 is usable. */
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if (CPU_FEATURES_CPU_P (cpu_features, FMA4))
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cpu_features->feature[index_arch_FMA4_Usable]
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|= bit_arch_FMA4_Usable;
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}
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}
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}
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static inline void
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init_cpu_features (struct cpu_features *cpu_features)
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{
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unsigned int ebx, ecx, edx;
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unsigned int family = 0;
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unsigned int model = 0;
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enum cpu_features_kind kind;
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#if !HAS_CPUID
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if (__get_cpuid_max (0, 0) == 0)
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{
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kind = arch_kind_other;
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goto no_cpuid;
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}
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#endif
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__cpuid (0, cpu_features->max_cpuid, ebx, ecx, edx);
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/* This spells out "GenuineIntel". */
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if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
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{
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unsigned int extended_model;
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kind = arch_kind_intel;
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get_common_indeces (cpu_features, &family, &model, &extended_model);
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if (family == 0x06)
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{
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ecx = cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx;
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model += extended_model;
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switch (model)
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{
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case 0x1c:
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case 0x26:
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/* BSF is slow on Atom. */
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cpu_features->feature[index_arch_Slow_BSF]
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|= bit_arch_Slow_BSF;
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break;
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case 0x57:
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/* Knights Landing. Enable Silvermont optimizations. */
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cpu_features->feature[index_arch_Prefer_No_VZEROUPPER]
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|= bit_arch_Prefer_No_VZEROUPPER;
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case 0x37:
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case 0x4a:
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case 0x4d:
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case 0x5a:
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case 0x5d:
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/* Unaligned load versions are faster than SSSE3
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on Silvermont. */
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#if index_arch_Fast_Unaligned_Load != index_arch_Prefer_PMINUB_for_stringop
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# error index_arch_Fast_Unaligned_Load != index_arch_Prefer_PMINUB_for_stringop
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#endif
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#if index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
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# error index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
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#endif
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#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
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# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
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#endif
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cpu_features->feature[index_arch_Fast_Unaligned_Load]
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|= (bit_arch_Fast_Unaligned_Load
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| bit_arch_Fast_Unaligned_Copy
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| bit_arch_Prefer_PMINUB_for_stringop
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| bit_arch_Slow_SSE4_2);
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break;
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default:
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/* Unknown family 0x06 processors. Assuming this is one
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of Core i3/i5/i7 processors if AVX is available. */
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if ((ecx & bit_cpu_AVX) == 0)
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break;
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case 0x1a:
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case 0x1e:
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case 0x1f:
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case 0x25:
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case 0x2c:
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case 0x2e:
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case 0x2f:
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/* Rep string instructions, copy backward, unaligned loads
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and pminub are fast on Intel Core i3, i5 and i7. */
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#if index_arch_Fast_Rep_String != index_arch_Fast_Copy_Backward
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# error index_arch_Fast_Rep_String != index_arch_Fast_Copy_Backward
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#endif
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#if index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Load
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# error index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Load
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#endif
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#if index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
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# error index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
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#endif
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#if index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
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# error index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
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#endif
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cpu_features->feature[index_arch_Fast_Rep_String]
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|= (bit_arch_Fast_Rep_String
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| bit_arch_Fast_Copy_Backward
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| bit_arch_Fast_Unaligned_Load
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| bit_arch_Fast_Unaligned_Copy
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| bit_arch_Prefer_PMINUB_for_stringop);
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break;
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}
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}
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/* Unaligned load with 256-bit AVX registers are faster on
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Intel processors with AVX2. */
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if (CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
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cpu_features->feature[index_arch_AVX_Fast_Unaligned_Load]
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|= bit_arch_AVX_Fast_Unaligned_Load;
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}
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/* This spells out "AuthenticAMD". */
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else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
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{
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unsigned int extended_model;
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kind = arch_kind_amd;
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get_common_indeces (cpu_features, &family, &model, &extended_model);
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ecx = cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx;
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unsigned int eax;
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__cpuid (0x80000000, eax, ebx, ecx, edx);
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if (eax >= 0x80000001)
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__cpuid (0x80000001,
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cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax,
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cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx,
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cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx);
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if (family == 0x15)
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{
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#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
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# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
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#endif
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/* "Excavator" */
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if (model >= 0x60 && model <= 0x7f)
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cpu_features->feature[index_arch_Fast_Unaligned_Load]
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|= (bit_arch_Fast_Unaligned_Load
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| bit_arch_Fast_Copy_Backward);
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}
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}
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else
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{
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kind = arch_kind_other;
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get_common_indeces (cpu_features, NULL, NULL, NULL);
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}
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/* Support i586 if CX8 is available. */
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if (CPU_FEATURES_CPU_P (cpu_features, CX8))
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cpu_features->feature[index_arch_I586] |= bit_arch_I586;
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/* Support i686 if CMOV is available. */
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if (CPU_FEATURES_CPU_P (cpu_features, CMOV))
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cpu_features->feature[index_arch_I686] |= bit_arch_I686;
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#if !HAS_CPUID
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no_cpuid:
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#endif
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cpu_features->family = family;
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cpu_features->model = model;
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cpu_features->kind = kind;
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}
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