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authorH.J. Lu <hjl.tools@gmail.com>2017-08-25 11:01:03 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-08-25 11:44:24 -0700
commitace02433fe2f0ce124d191bb273f738ef56fe387 (patch)
tree95f8ae66e11e12d68f2cbaad727a82db21f6b829
parent7ab70c98e87b6fbcb3c2c02075b0949ed239ad7e (diff)
downloadtermbaud-hjl/pr21967/master.tar.gz
termbaud-hjl/pr21967/master.tar.xz
termbaud-hjl/pr21967/master.zip
x86: Add MathVec_Prefer_No_AVX512 to cpu-features [BZ #21967]hjl/pr21967/master
AVX512 functions in mathvec are used on machines with AVX512. An AVX2 wrapper is also provided and it can be used when the AVX512 version isn't profitable. MathVec_Prefer_No_AVX512 is addded to cpu-features. If glibc.tune.hwcaps=MathVec_Prefer_No_AVX512 is set in GLIBC_TUNABLES environment variable, the AVX2 wrapper will be used. [BZ #21967] * sysdeps/x86/cpu-features.h (bit_arch_MathVec_Prefer_No_AVX512): New. (index_arch_MathVec_Prefer_No_AVX512): Likewise. * sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)): Handle MathVec_Prefer_No_AVX512.
-rw-r--r--sysdeps/x86/cpu-features.h2
-rw-r--r--sysdeps/x86/cpu-tunables.c7
-rw-r--r--sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h13
3 files changed, 17 insertions, 5 deletions
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index 9e01781424a..a032a2e168e 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -40,6 +40,7 @@
#define bit_arch_Use_dl_runtime_resolve_opt (1 << 20)
#define bit_arch_Use_dl_runtime_resolve_slow (1 << 21)
#define bit_arch_Prefer_No_AVX512 (1 << 22)
+#define bit_arch_MathVec_Prefer_No_AVX512 (1 << 23)
/* CPUID Feature flags. */
@@ -239,6 +240,7 @@ extern const struct cpu_features *__get_cpu_features (void)
# define index_arch_Use_dl_runtime_resolve_opt FEATURE_INDEX_1
# define index_arch_Use_dl_runtime_resolve_slow FEATURE_INDEX_1
# define index_arch_Prefer_No_AVX512 FEATURE_INDEX_1
+# define index_arch_MathVec_Prefer_No_AVX512 FEATURE_INDEX_1
#endif /* !__ASSEMBLER__ */
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
index 0ab708cca80..ec72d86f082 100644
--- a/sysdeps/x86/cpu-tunables.c
+++ b/sysdeps/x86/cpu-tunables.c
@@ -303,6 +303,13 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
disable, 23);
}
break;
+ case 24:
+ {
+ CHECK_GLIBC_IFUNC_ARCH_NEED_ARCH_BOTH
+ (n, cpu_features, MathVec_Prefer_No_AVX512,
+ AVX512F_Usable, disable, 24);
+ }
+ break;
case 26:
{
CHECK_GLIBC_IFUNC_ARCH_NEED_CPU_BOTH
diff --git a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h
index 1857e1f7604..fffc9da114f 100644
--- a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h
+++ b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx512.h
@@ -32,11 +32,14 @@ IFUNC_SELECTOR (void)
{
const struct cpu_features* cpu_features = __get_cpu_features ();
- if (CPU_FEATURES_ARCH_P (cpu_features, AVX512DQ_Usable))
- return OPTIMIZE (skx);
-
- if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable))
- return OPTIMIZE (knl);
+ if (!CPU_FEATURES_ARCH_P (cpu_features, MathVec_Prefer_No_AVX512))
+ {
+ if (CPU_FEATURES_ARCH_P (cpu_features, AVX512DQ_Usable))
+ return OPTIMIZE (skx);
+
+ if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable))
+ return OPTIMIZE (knl);
+ }
return OPTIMIZE (avx2_wrapper);
}