From 905947c30455bea5eed42cdffd771a11b1554f1d Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 20 Jun 2017 08:33:29 -0700 Subject: [PATCH] tunables: Add IFUNC selection and cache sizes The current IFUNC selection is based on microbenchmarks in glibc. It should give the best performance for most workloads. But other choices may have better performance for a particular workload or on the hardware which wasn't available at the selection was made. The environment variable, GLIBC_TUNABLES=glibc.tune.ifunc=-xxx,yyy,-zzz...., can be used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature yyy and zzz, where the feature name is case-sensitive and has to match the ones in cpu-features.h. It can be used by glibc developers to override the IFUNC selection to tune for a new processor or improve performance for a particular workload. It isn't intended for normal end users. NOTE: the IFUNC selection may change over time. Please check all multiarch implementations when experimenting. Also, GLIBC_TUNABLES=glibc.tune.x86_non_temporal_threshold=NUMBER is provided to set threshold to use non temporal store to NUMBER, GLIBC_TUNABLES=glibc.tune.x86_data_cache_size=NUMBER to set data cache size, GLIBC_TUNABLES=glibc.tune.x86_shared_cache_size=NUMBER to set shared cache size. * elf/dl-tunables.list (tune): Add ifunc, x86_non_temporal_threshold, x86_data_cache_size and x86_shared_cache_size. * manual/tunables.texi: Document glibc.tune.ifunc, glibc.tune.x86_data_cache_size, glibc.tune.x86_shared_cache_size and glibc.tune.x86_non_temporal_threshold. * sysdeps/unix/sysv/linux/x86/dl-sysdep.c: New file. * sysdeps/x86/cpu-tunables.c: Likewise. * sysdeps/x86/cacheinfo.c (init_cacheinfo): Check and get data cache size, shared cache size and non temporal threshold from cpu_features. * sysdeps/x86/cpu-features.c [HAVE_TUNABLES] (TUNABLE_NAMESPACE): New. [HAVE_TUNABLES] Include . [HAVE_TUNABLES] Include . [HAVE_TUNABLES] (TUNABLE_CALLBACK (set_ifunc)): Likewise. [HAVE_TUNABLES] (init_cpu_features): Use TUNABLE_GET to set IFUNC selection, data cache size, shared cache size and non temporal threshold. * sysdeps/x86/cpu-features.h (cpu_features): Add data_cache_size, shared_cache_size and non_temporal_threshold. --- ChangeLog | 25 ++ elf/dl-tunables.list | 16 ++ manual/tunables.texi | 36 +++ sysdeps/unix/sysv/linux/x86/dl-sysdep.c | 21 ++ sysdeps/x86/cacheinfo.c | 10 +- sysdeps/x86/cpu-features.c | 19 ++ sysdeps/x86/cpu-features.h | 8 + sysdeps/x86/cpu-tunables.c | 330 ++++++++++++++++++++++++ 8 files changed, 464 insertions(+), 1 deletion(-) create mode 100644 sysdeps/unix/sysv/linux/x86/dl-sysdep.c create mode 100644 sysdeps/x86/cpu-tunables.c diff --git a/ChangeLog b/ChangeLog index 80bb1f847e..e44f7bd5c4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,28 @@ +2017-06-20 H.J. Lu + Erich Elsen + + * elf/dl-tunables.list (tune): Add ifunc, + x86_non_temporal_threshold, + x86_data_cache_size and x86_shared_cache_size. + * manual/tunables.texi: Document glibc.tune.ifunc, + glibc.tune.x86_data_cache_size, glibc.tune.x86_shared_cache_size + and glibc.tune.x86_non_temporal_threshold. + * sysdeps/unix/sysv/linux/x86/dl-sysdep.c: New file. + * sysdeps/x86/cpu-tunables.c: Likewise. + * sysdeps/x86/cacheinfo.c + (init_cacheinfo): Check and get data cache size, shared cache + size and non temporal threshold from cpu_features. + * sysdeps/x86/cpu-features.c [HAVE_TUNABLES] (TUNABLE_NAMESPACE): + New. + [HAVE_TUNABLES] Include . + [HAVE_TUNABLES] Include . + [HAVE_TUNABLES] (TUNABLE_CALLBACK (set_ifunc)): Likewise. + [HAVE_TUNABLES] (init_cpu_features): Use TUNABLE_GET to set + IFUNC selection, data cache size, shared cache size and non + temporal threshold. + * sysdeps/x86/cpu-features.h (cpu_features): Add data_cache_size, + shared_cache_size and non_temporal_threshold. + 2017-06-20 Wilco Dijkstra * benchtests/README: Describe workload feature. diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list index 41ce9afa28..3247d49b59 100644 --- a/elf/dl-tunables.list +++ b/elf/dl-tunables.list @@ -82,6 +82,22 @@ glibc { type: UINT_64 env_alias: LD_HWCAP_MASK default: HWCAP_IMPORTANT + } + ifunc { + type: STRING + security_level: SXID_IGNORE + } + x86_non_temporal_threshold { + type: SIZE_T + security_level: SXID_IGNORE + } + x86_data_cache_size { + type: SIZE_T + security_level: SXID_IGNORE + } + x86_shared_cache_size { + type: SIZE_T + security_level: SXID_IGNORE } } } diff --git a/manual/tunables.texi b/manual/tunables.texi index c9a4cb7fe5..3263f944c5 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -198,6 +198,14 @@ is 8 times the number of cores online. @cindex hardware capability tunables @cindex hwcap tunables @cindex tunables, hwcap +@cindex ifunc tunables +@cindex tunables, ifunc +@cindex data_cache_size tunables +@cindex tunables, data_cache_size +@cindex shared_cache_size tunables +@cindex tunables, shared_cache_size +@cindex non_temporal_threshold tunables +@cindex tunables, non_temporal_threshold @deftp {Tunable namespace} glibc.tune Behavior of @theglibc{} can be tuned to assume specific hardware capabilities @@ -213,3 +221,31 @@ extensions available in the processor at runtime for some architectures. The @code{glibc.tune.hwcap_mask} tunable allows the user to mask out those capabilities at runtime, thus disabling use of those extensions. @end deftp + +@deftp Tunable glibc.tune.ifunc +The @code{glibc.tune.ifunc=-xxx,yyy,-zzz...} tunable allows the user to +enable CPU/ARCH feature @code{yyy}, disable CPU/ARCH feature @code{xxx} +and @code{zzz} where the feature name is case-sensitive and has to match +the ones in @code{sysdeps/x86/cpu-features.h}. + +This tunable is specific to i386 and x86-64. +@end deftp + +@deftp Tunable glibc.tune.x86_data_cache_size +The @code{glibc.tune.x86_data_cache_size} tunable allows the user to set +data cache size in bytes for use in memory and string routines. + +This tunable is specific to i386 and x86-64. +@end deftp + +@deftp Tunable glibc.tune.x86_shared_cache_size +The @code{glibc.tune.x86_shared_cache_size} tunable allows the user to +set shared cache size in bytes for use in memory and string routines. +@end deftp + +@deftp Tunable glibc.tune.x86_non_temporal_threshold +The @code{glibc.tune.x86_non_temporal_threshold} tunable allows the user +to set threshold in bytes for non temporal store. + +This tunable is specific to i386 and x86-64. +@end deftp diff --git a/sysdeps/unix/sysv/linux/x86/dl-sysdep.c b/sysdeps/unix/sysv/linux/x86/dl-sysdep.c new file mode 100644 index 0000000000..64eb0d7956 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/dl-sysdep.c @@ -0,0 +1,21 @@ +/* Operating system support for run-time dynamic linker. X86 version. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include diff --git a/sysdeps/x86/cacheinfo.c b/sysdeps/x86/cacheinfo.c index 8000fd1e99..9542dfba80 100644 --- a/sysdeps/x86/cacheinfo.c +++ b/sysdeps/x86/cacheinfo.c @@ -752,6 +752,9 @@ intel_bug_no_cache_info: #endif } + if (cpu_features->data_cache_size != 0) + data = cpu_features->data_cache_size; + if (data > 0) { __x86_raw_data_cache_size_half = data / 2; @@ -762,6 +765,9 @@ intel_bug_no_cache_info: __x86_data_cache_size = data; } + if (cpu_features->shared_cache_size != 0) + shared = cpu_features->shared_cache_size; + if (shared > 0) { __x86_raw_shared_cache_size_half = shared / 2; @@ -777,7 +783,9 @@ intel_bug_no_cache_info: store becomes faster on a 8-core processor. This is the 3/4 of the total shared cache size. */ __x86_shared_non_temporal_threshold - = __x86_shared_cache_size * threads * 3 / 4; + = (cpu_features->non_temporal_threshold != 0 + ? cpu_features->non_temporal_threshold + : __x86_shared_cache_size * threads * 3 / 4); } #endif diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 4288001cdd..76f053af80 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -20,6 +20,15 @@ #include #include +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE tune +# include /* Get STDOUT_FILENO for _dl_printf. */ +# include + +extern void TUNABLE_CALLBACK (set_ifunc) (tunable_val_t *) + attribute_hidden; +#endif + static void get_common_indeces (struct cpu_features *cpu_features, unsigned int *family, unsigned int *model, @@ -312,6 +321,16 @@ no_cpuid: cpu_features->model = model; cpu_features->kind = kind; +#if HAVE_TUNABLES + TUNABLE_GET (ifunc, tunable_val_t *, TUNABLE_CALLBACK (set_ifunc)); + cpu_features->non_temporal_threshold + = TUNABLE_GET (x86_non_temporal_threshold, long int, NULL); + cpu_features->data_cache_size + = TUNABLE_GET (x86_data_cache_size, long int, NULL); + cpu_features->shared_cache_size + = TUNABLE_GET (x86_shared_cache_size, long int, NULL); +#endif + /* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */ GLRO(dl_platform) = NULL; GLRO(dl_hwcap) = 0; diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h index f2329ea696..fef5e1894f 100644 --- a/sysdeps/x86/cpu-features.h +++ b/sysdeps/x86/cpu-features.h @@ -215,6 +215,14 @@ struct cpu_features unsigned int family; unsigned int model; unsigned int feature[FEATURE_INDEX_MAX]; + /* Data cache size for use in memory and string routines, typically + L1 size. */ + long int data_cache_size; + /* Shared cache size for use in memory and string routines, typically + L2 or L3 size. */ + long int shared_cache_size; + /* Threshold to use non temporal store. */ + long int non_temporal_threshold; }; /* Used from outside of glibc to get access to the CPU features diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c new file mode 100644 index 0000000000..9258fb41de --- /dev/null +++ b/sysdeps/x86/cpu-tunables.c @@ -0,0 +1,330 @@ +/* x86 CPU feature tuning. + This file is part of the GNU C Library. + Copyright (C) 2017 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#if HAVE_TUNABLES +# define TUNABLE_NAMESPACE tune +# include +# include +# include /* Get STDOUT_FILENO for _dl_printf. */ +# include +# include +# include +# include + +/* We can't use IFUNC memcmp nor strlen in init_cpu_features from libc.a + since IFUNC must be set up by init_cpu_features. */ +# if defined USE_MULTIARCH && !defined SHARED +# ifdef __x86_64__ +# define DEFAULT_MEMCMP __memcmp_sse2 +# define DEFAULT_STRLEN __strlen_sse2 +# else +# define DEFAULT_MEMCMP __memcmp_ia32 +# define DEFAULT_STRLEN strlen +# endif +extern __typeof (memcmp) DEFAULT_MEMCMP; +extern __typeof (strlen) DEFAULT_STRLEN; +# else +# define DEFAULT_MEMCMP memcmp +# define DEFAULT_STRLEN strlen +# endif + +# define CHECK_GLIBC_IFUNC_CPU_OFF(f, cpu_features, name, len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (!DEFAULT_MEMCMP (f, #name, len)) \ + { \ + cpu_features->cpuid[index_cpu_##name].reg_##name \ + &= ~bit_cpu_##name; \ + break; \ + } + +/* Disable an ARCH feature NAME. We don't enable an ARCH feature which + isn't available. */ +# define CHECK_GLIBC_IFUNC_ARCH_OFF(f, cpu_features, name, len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (!DEFAULT_MEMCMP (f, #name, len)) \ + { \ + cpu_features->feature[index_arch_##name] \ + &= ~bit_arch_##name; \ + break; \ + } + +/* Enable/disable an ARCH feature NAME. */ +# define CHECK_GLIBC_IFUNC_ARCH_BOTH(f, cpu_features, name, disable, \ + len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (!DEFAULT_MEMCMP (f, #name, len)) \ + { \ + if (disable) \ + cpu_features->feature[index_arch_##name] \ + &= ~bit_arch_##name; \ + else \ + cpu_features->feature[index_arch_##name] \ + |= bit_arch_##name; \ + break; \ + } + +/* Enable/disable an ARCH feature NAME. Enable an ARCH feature only + if the ARCH feature NEED is also enabled. */ +# define CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH(f, cpu_features, name, \ + need, disable, len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (!DEFAULT_MEMCMP (f, #name, len)) \ + { \ + if (disable) \ + cpu_features->feature[index_arch_##name] \ + &= ~bit_arch_##name; \ + else if (CPU_FEATURES_ARCH_P (cpu_features, need)) \ + cpu_features->feature[index_arch_##name] \ + |= bit_arch_##name; \ + break; \ + } + +/* Enable/disable an ARCH feature NAME. Enable an ARCH feature only + if the CPU feature NEED is also enabled. */ +# define CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH(f, cpu_features, name, \ + need, disable, len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (!DEFAULT_MEMCMP (f, #name, len)) \ + { \ + if (disable) \ + cpu_features->feature[index_arch_##name] \ + &= ~bit_arch_##name; \ + else if (CPU_FEATURES_CPU_P (cpu_features, need)) \ + cpu_features->feature[index_arch_##name] \ + |= bit_arch_##name; \ + break; \ + } + +attribute_hidden +void +TUNABLE_CALLBACK (set_ifunc) (tunable_val_t *valp) +{ + /* The current IFUNC selection is based on microbenchmarks in glibc. + It should give the best performance for most workloads. But other + choices may have better performance for a particular workload or on + the hardware which wasn't available when the selection was made. + The environment variable, GLIBC_IFUNC=-xxx,yyy,-zzz...., can be + used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature yyy + and zzz, where the feature name is case-sensitive and has to match + the ones in cpu-features.h. It can be used by glibc developers to + tune for a new processor or override the IFUNC selection to improve + performance for a particular workload. + + Since all CPU/ARCH features are hardware optimizations without + security implication, except for Prefer_MAP_32BIT_EXEC, which can + only be disabled, we check GLIBC_IFUNC for programs, including + set*id ones. + + NOTE: the IFUNC selection may change over time. Please check all + multiarch implementations when experimenting. */ + + const char *p = valp->strval; + struct cpu_features *cpu_features = &GLRO(dl_x86_cpu_features); + const char *end = p + DEFAULT_STRLEN (p); + size_t len; + + do + { + const char *c, *n; + bool disable; + size_t nl; + + for (c = p; *c != ','; c++) + if (c >= end) + break; + + len = c - p; + disable = *p == '-'; + if (disable) + { + n = p + 1; + nl = len - 1; + } + else + { + n = p; + nl = len; + } + switch (nl) + { + default: + break; + case 3: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX, 3); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, CX8, 3); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, FMA, 3); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, HTT, 3); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, RTM, 3); + } + break; + case 4: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX2, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, BMI1, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, BMI2, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, CMOV, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, ERMS, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, FMA4, 4); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE2, 4); + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, I586, 4); + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, I686, 4); + } + break; + case 5: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, LZCNT, 5); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, MOVBE, 5); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSSE3, 5); + } + break; + case 6: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, POPCNT, 6); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE4_1, 6); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSE4_2, 6); + } + break; + case 7: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512F, 7); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, OSXSAVE, 7); + } + break; + case 8: + if (disable) + { + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512CD, 8); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512BW, 8); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512DQ, 8); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512ER, 8); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512PF, 8); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, AVX512VL, 8); + } + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Slow_BSF, + disable, 8); + break; + case 10: + if (disable) + { + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, AVX_Usable, + 10); + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, FMA_Usable, + 10); + } + break; + case 11: + if (disable) + { + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, AVX2_Usable, + 11); + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, FMA4_Usable, + 11); + } + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Prefer_ERMS, + disable, 11); + CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH (n, cpu_features, + Slow_SSE4_2, SSE4_2, + disable, 11); + break; + case 14: + if (disable) + { + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, + AVX512F_Usable, 14); + } + break; + case 15: + if (disable) + { + CHECK_GLIBC_IFUNC_ARCH_OFF (n, cpu_features, + AVX512DQ_Usable, 15); + } + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, Fast_Rep_String, + disable, 15); + break; + case 16: + { + CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH + (n, cpu_features, Prefer_No_AVX512, AVX512F_Usable, + disable, 16); + } + break; + case 18: + { + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, + Fast_Copy_Backward, disable, + 18); + } + break; + case 19: + { + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, + Fast_Unaligned_Load, disable, + 19); + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, + Fast_Unaligned_Copy, disable, + 19); + } + break; + case 20: + { + CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH + (n, cpu_features, Prefer_No_VZEROUPPER, AVX_Usable, + disable, 20); + } + break; + case 21: + { + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, + Prefer_MAP_32BIT_EXEC, disable, + 21); + } + break; + case 23: + { + CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH + (n, cpu_features, AVX_Fast_Unaligned_Load, AVX_Usable, + disable, 23); + } + break; + case 26: + { + CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH + (n, cpu_features, Prefer_PMINUB_for_stringop, SSE2, + disable, 26); + } + break; + case 27: + { + CHECK_GLIBC_IFUNC_ARCH_BOTH (n, cpu_features, + Use_dl_runtime_resolve_slow, + disable, 27); + } + break; + } + p += len + 1; + } + while (p < end); +} +#endif -- 2.43.5