diff options
Diffstat (limited to 'sysdeps/x86')
| -rw-r--r-- | sysdeps/x86/cacheinfo.h | 9 | ||||
| -rw-r--r-- | sysdeps/x86/cpu-features.c | 5 | ||||
| -rw-r--r-- | sysdeps/x86/include/cpu-features-preferred_feature_index_1.def | 1 | ||||
| -rw-r--r-- | sysdeps/x86/sysdep.h | 5 |
4 files changed, 20 insertions, 0 deletions
diff --git a/sysdeps/x86/cacheinfo.h b/sysdeps/x86/cacheinfo.h index eba8dbc4a6..41d2c81369 100644 --- a/sysdeps/x86/cacheinfo.h +++ b/sysdeps/x86/cacheinfo.h @@ -49,6 +49,11 @@ long int __x86_rep_stosb_threshold attribute_hidden = 2048; /* Threshold to stop using Enhanced REP MOVSB. */ long int __x86_rep_movsb_stop_threshold attribute_hidden; +/* A bit-wise OR of string/memory requirements for optimal performance + e.g. X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB. These bits + are used at runtime to tune implementation behavior. */ +int __x86_string_control attribute_hidden; + static void init_cacheinfo (void) { @@ -71,5 +76,9 @@ init_cacheinfo (void) __x86_rep_movsb_threshold = cpu_features->rep_movsb_threshold; __x86_rep_stosb_threshold = cpu_features->rep_stosb_threshold; __x86_rep_movsb_stop_threshold = cpu_features->rep_movsb_stop_threshold; + + if (CPU_FEATURES_ARCH_P (cpu_features, Avoid_Short_Distance_REP_MOVSB)) + __x86_string_control + |= X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB; } #endif diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 706a172ba9..645bba6314 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -555,6 +555,11 @@ init_cpu_features (struct cpu_features *cpu_features) cpu_features->preferred[index_arch_Prefer_AVX2_STRCMP] |= bit_arch_Prefer_AVX2_STRCMP; } + + /* Avoid avoid short distance REP MOVSB on processor with FSRM. */ + if (CPU_FEATURES_CPU_P (cpu_features, FSRM)) + cpu_features->preferred[index_arch_Avoid_Short_Distance_REP_MOVSB] + |= bit_arch_Avoid_Short_Distance_REP_MOVSB; } /* This spells out "AuthenticAMD" or "HygonGenuine". */ else if ((ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65) diff --git a/sysdeps/x86/include/cpu-features-preferred_feature_index_1.def b/sysdeps/x86/include/cpu-features-preferred_feature_index_1.def index 133aab19f1..d7c93f00c5 100644 --- a/sysdeps/x86/include/cpu-features-preferred_feature_index_1.def +++ b/sysdeps/x86/include/cpu-features-preferred_feature_index_1.def @@ -33,3 +33,4 @@ BIT (Prefer_No_AVX512) BIT (MathVec_Prefer_No_AVX512) BIT (Prefer_FSRM) BIT (Prefer_AVX2_STRCMP) +BIT (Avoid_Short_Distance_REP_MOVSB) diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h index 51c069bfe1..cac1d762fb 100644 --- a/sysdeps/x86/sysdep.h +++ b/sysdeps/x86/sysdep.h @@ -57,6 +57,11 @@ enum cf_protection_level #define STATE_SAVE_MASK \ ((1 << 1) | (1 << 2) | (1 << 3) | (1 << 5) | (1 << 6) | (1 << 7)) +/* Constants for bits in __x86_string_control: */ + +/* Avoid short distance REP MOVSB. */ +#define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB (1 << 0) + #ifdef __ASSEMBLER__ /* Syntactic details of assembler. */ |