diff options
Diffstat (limited to 'sysdeps/x86/cpu-tunables.c')
| -rw-r--r-- | sysdeps/x86/cpu-tunables.c | 29 |
1 files changed, 11 insertions, 18 deletions
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 9258fb41de..872dd1267f 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -31,16 +31,12 @@ # 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) \ @@ -112,30 +108,27 @@ extern __typeof (strlen) DEFAULT_STRLEN; attribute_hidden void -TUNABLE_CALLBACK (set_ifunc) (tunable_val_t *valp) +TUNABLE_CALLBACK (set_hwcaps) (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. + The environment variable: - 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. + GLIBC_TUNABLES=glibc.tune.hwcaps=-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. 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 @@ -145,7 +138,7 @@ TUNABLE_CALLBACK (set_ifunc) (tunable_val_t *valp) size_t nl; for (c = p; *c != ','; c++) - if (c >= end) + if (*c == '\0') break; len = c - p; @@ -325,6 +318,6 @@ TUNABLE_CALLBACK (set_ifunc) (tunable_val_t *valp) } p += len + 1; } - while (p < end); + while (*p != '\0'); } #endif |