mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 00:31:08 +00:00
ecbbadbf10
1. Divide architecture features into the usable features and the preferred
features. The usable features are for correctness and can be exported in
a stable ABI. The preferred features are for performance and only for
glibc internal use.
2. Change struct cpu_features to
struct cpu_features
{
struct cpu_features_basic basic;
unsigned int *usable_p;
struct cpuid_registers cpuid[COMMON_CPUID_INDEX_MAX];
unsigned int usable[USABLE_FEATURE_INDEX_MAX];
unsigned int preferred[PREFERRED_FEATURE_INDEX_MAX];
...
};
and initialize usable_p to pointer to the usable arary so that
struct cpu_features
{
struct cpu_features_basic basic;
unsigned int *usable_p;
struct cpuid_registers cpuid[COMMON_CPUID_INDEX_MAX];
};
can be exported via a stable ABI. The cpuid and usable arrays can be
expanded with backward binary compatibility for both .o and .so files.
3. Add COMMON_CPUID_INDEX_7_ECX_1 for AVX512_BF16.
4. Detect ENQCMD, PKS, AVX512_VP2INTERSECT, MD_CLEAR, SERIALIZE, HYBRID,
TSXLDTRK, L1D_FLUSH, CORE_CAPABILITIES and AVX512_BF16.
5. Rename CAPABILITIES to ARCH_CAPABILITIES.
6. Check if AVX512_VP2INTERSECT, AVX512_BF16 and PKU are usable.
7. Update CPU feature detection test.
367 lines
11 KiB
C
367 lines
11 KiB
C
/* x86 CPU feature tuning.
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This file is part of the GNU C Library.
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Copyright (C) 2017-2020 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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<https://www.gnu.org/licenses/>. */
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#if HAVE_TUNABLES
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# define TUNABLE_NAMESPACE cpu
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# include <stdbool.h>
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# include <stdint.h>
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# include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
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# include <elf/dl-tunables.h>
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# include <string.h>
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# include <cpu-features.h>
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# include <ldsodefs.h>
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/* We can't use IFUNC memcmp nor strlen in init_cpu_features from libc.a
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since IFUNC must be set up by init_cpu_features. */
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# if defined USE_MULTIARCH && !defined SHARED
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# ifdef __x86_64__
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# define DEFAULT_MEMCMP __memcmp_sse2
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# else
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# define DEFAULT_MEMCMP __memcmp_ia32
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# endif
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extern __typeof (memcmp) DEFAULT_MEMCMP;
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# else
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# define DEFAULT_MEMCMP memcmp
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# endif
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# define CHECK_GLIBC_IFUNC_CPU_OFF(f, cpu_features, name, len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!DEFAULT_MEMCMP (f, #name, len)) \
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{ \
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cpu_features->cpuid[index_cpu_##name].reg_##name \
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&= ~bit_cpu_##name; \
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break; \
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}
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/* Disable an ARCH feature NAME. We don't enable an ARCH feature which
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isn't available. */
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# define CHECK_GLIBC_IFUNC_ARCH_OFF(f, cpu_features, name, len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!DEFAULT_MEMCMP (f, #name, len)) \
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{ \
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cpu_features->feature_##name[index_arch_##name] \
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&= ~bit_arch_##name; \
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break; \
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}
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/* Enable/disable an ARCH feature NAME. */
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# define CHECK_GLIBC_IFUNC_ARCH_BOTH(f, cpu_features, name, disable, \
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len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!DEFAULT_MEMCMP (f, #name, len)) \
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{ \
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if (disable) \
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cpu_features->feature_##name[index_arch_##name] \
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&= ~bit_arch_##name; \
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else \
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cpu_features->feature_##name[index_arch_##name] \
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|= bit_arch_##name; \
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break; \
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}
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/* Enable/disable an ARCH feature NAME. Enable an ARCH feature only
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if the ARCH feature NEED is also enabled. */
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# define CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH(f, cpu_features, name, \
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need, disable, len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!DEFAULT_MEMCMP (f, #name, len)) \
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{ \
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if (disable) \
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cpu_features->feature_##name[index_arch_##name] \
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&= ~bit_arch_##name; \
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else if (CPU_FEATURES_ARCH_P (cpu_features, need)) \
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cpu_features->feature_##name[index_arch_##name] \
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|= bit_arch_##name; \
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break; \
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}
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/* Enable/disable an ARCH feature NAME. Enable an ARCH feature only
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if the CPU feature NEED is also enabled. */
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# define CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH(f, cpu_features, name, \
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need, disable, len) \
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_Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \
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if (!DEFAULT_MEMCMP (f, #name, len)) \
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{ \
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if (disable) \
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cpu_features->feature_##name[index_arch_##name] \
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&= ~bit_arch_##name; \
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else if (CPU_FEATURES_CPU_P (cpu_features, need)) \
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cpu_features->feature_##name[index_arch_##name] \
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|= bit_arch_##name; \
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break; \
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}
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attribute_hidden
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void
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TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
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{
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/* The current IFUNC selection is based on microbenchmarks in glibc.
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It should give the best performance for most workloads. But other
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choices may have better performance for a particular workload or on
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the hardware which wasn't available when the selection was made.
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The environment variable:
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GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,-zzz,....
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can be used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature
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yyy and zzz, where the feature name is case-sensitive and has to
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match the ones in cpu-features.h. It can be used by glibc developers
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to tune for a new processor or override the IFUNC selection to
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improve performance for a particular workload.
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NOTE: the IFUNC selection may change over time. Please check all
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multiarch implementations when experimenting. */
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const char *p = valp->strval;
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struct cpu_features *cpu_features = &GLRO(dl_x86_cpu_features);
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size_t len;
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do
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{
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const char *c, *n;
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bool disable;
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size_t nl;
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for (c = p; *c != ','; c++)
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if (*c == '\0')
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break;
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len = c - p;
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disable = *p == '-';
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if (disable)
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{
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n = p + 1;
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nl = len - 1;
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}
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else
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{
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n = p;
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nl = len;
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}
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switch (nl)
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{
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default:
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break;
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case 3:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, CX8, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, FMA, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, HTT, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, IBT, 3);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, RTM, 3);
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}
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break;
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case 4:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX2, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, BMI1, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, BMI2, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, CMOV, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, ERMS, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, FMA4, 4);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE2, 4);
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, I586, 4);
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, I686, 4);
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}
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break;
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case 5:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, LZCNT, 5);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, MOVBE, 5);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SHSTK, 5);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSSE3, 5);
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}
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break;
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case 6:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, POPCNT, 6);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE4_1, 6);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE4_2, 6);
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}
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break;
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case 7:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512F, 7);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, OSXSAVE, 7);
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}
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break;
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case 8:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512CD, 8);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512BW, 8);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512DQ, 8);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512ER, 8);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512PF, 8);
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CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512VL, 8);
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}
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Slow_BSF,
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disable, 8);
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break;
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case 10:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, AVX_Usable,
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10);
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, FMA_Usable,
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10);
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}
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break;
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case 11:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, AVX2_Usable,
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11);
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, FMA4_Usable,
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11);
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}
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Prefer_ERMS,
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disable, 11);
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CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH (n, cpu_features,
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Slow_SSE4_2, SSE4_2,
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disable, 11);
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Prefer_FSRM,
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disable, 11);
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break;
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case 13:
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if (disable)
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{
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/* Update xsave_state_size to XSAVE state size. */
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cpu_features->xsave_state_size
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= cpu_features->xsave_state_full_size;
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features,
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XSAVEC_Usable, 13);
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}
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break;
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case 14:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features,
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AVX512F_Usable, 14);
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}
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break;
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case 15:
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if (disable)
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{
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CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features,
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AVX512DQ_Usable, 15);
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}
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Fast_Rep_String,
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disable, 15);
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break;
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case 16:
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{
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CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH
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(n, cpu_features, Prefer_No_AVX512, AVX512F_Usable,
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disable, 16);
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}
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break;
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case 18:
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{
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features,
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Fast_Copy_Backward, disable,
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18);
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}
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break;
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case 19:
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{
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features,
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Fast_Unaligned_Load, disable,
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19);
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features,
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Fast_Unaligned_Copy, disable,
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19);
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}
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break;
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case 20:
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{
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CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH
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(n, cpu_features, Prefer_No_VZEROUPPER, AVX_Usable,
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disable, 20);
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}
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break;
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case 21:
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{
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CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features,
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Prefer_MAP_32BIT_EXEC, disable,
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21);
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}
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break;
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case 23:
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{
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CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH
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(n, cpu_features, AVX_Fast_Unaligned_Load, AVX_Usable,
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disable, 23);
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}
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break;
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case 24:
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{
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CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH
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(n, cpu_features, MathVec_Prefer_No_AVX512,
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AVX512F_Usable, disable, 24);
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}
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break;
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case 26:
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{
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CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH
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(n, cpu_features, Prefer_PMINUB_for_stringop, SSE2,
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disable, 26);
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}
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break;
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}
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p += len + 1;
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}
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while (*p != '\0');
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}
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# if CET_ENABLED
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attribute_hidden
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void
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TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp)
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{
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if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
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GL(dl_x86_feature_control).ibt = cet_always_on;
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else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
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GL(dl_x86_feature_control).ibt = cet_always_off;
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else if (DEFAULT_MEMCMP (valp->strval, "permissive",
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sizeof ("permissive")) == 0)
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GL(dl_x86_feature_control).ibt = cet_permissive;
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}
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attribute_hidden
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void
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TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *valp)
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{
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if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
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GL(dl_x86_feature_control).shstk = cet_always_on;
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else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
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GL(dl_x86_feature_control).shstk = cet_always_off;
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else if (DEFAULT_MEMCMP (valp->strval, "permissive",
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sizeof ("permissive")) == 0)
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GL(dl_x86_feature_control).shstk = cet_permissive;
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}
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# endif
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#endif
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