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Re: [PATCH RFC] X86_64 Avx2 Detection
- From: ling dot ma dot program at gmail dot com
- To: hjl dot tools at gmail dot com
- Cc: libc-alpha at sourceware dot org, neleai at seznam dot cz, aj at suse dot com, liubov dot dmitrieva at gmail dot com, Sihai Yao <sihai dot ysh at alibaba-inc dot com>
- Date: Mon, 14 Apr 2014 08:53:51 -0400
- Subject: Re: [PATCH RFC] X86_64 Avx2 Detection
- Authentication-results: sourceware.org; auth=none
From: Sihai Yao <sihai.ysh@alibaba-inc.com>
This patch sets bit_AVX2_Usable of __cpu_features.feature by checking
COMMON_CPUID_INDEX_7 for Haswell. Architecture related assembler file
can use this bit to determine calling path.
---
This version removed the unrelated cpu module branch code and FEATURE_INDEX_7,
which is unusefull for AVX
ChangeLog | 8 ++++++++
sysdeps/x86_64/multiarch/ifunc-defines.sym | 1 +
sysdeps/x86_64/multiarch/init-arch.c | 3 +++
sysdeps/x86_64/multiarch/init-arch.h | 8 ++++++++
4 files changed, 20 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index fb0177d..ba8980c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-04-04 Sihai Yao <sihai.ysh@alibaba-inc.com>
+ * sysdeps/x86_64/multiarch/ifunc-defines.sym: Add COMMON_CPU_INDEX_7 and
+ FEATURE_INDEX_7.
+ * sysdeps/x86_64/multiarch/init-arch.c: Add AVX2 detection from cpu
+ features word of COMMON_CPUID_INDEX_7.
+ * sysdeps/x86_64/multiarch/init-arch.h: Add bit_AVX2_Usable and
+ index_AVX2_Usable for future assembly code to determing calling path.
+
2014-04-10 Torvald Riegel <triegel@redhat.com>
* benchtests/pthread_once-inputs: New file.
diff --git a/sysdeps/x86_64/multiarch/ifunc-defines.sym b/sysdeps/x86_64/multiarch/ifunc-defines.sym
index eb1538a..a410d88 100644
--- a/sysdeps/x86_64/multiarch/ifunc-defines.sym
+++ b/sysdeps/x86_64/multiarch/ifunc-defines.sym
@@ -17,4 +17,5 @@ FEATURE_OFFSET offsetof (struct cpu_features, feature)
FEATURE_SIZE sizeof (unsigned int)
COMMON_CPUID_INDEX_1
+COMMON_CPUID_INDEX_7
FEATURE_INDEX_1
diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
index db74d97..2a6dcb7 100644
--- a/sysdeps/x86_64/multiarch/init-arch.c
+++ b/sysdeps/x86_64/multiarch/init-arch.c
@@ -167,6 +167,9 @@ __init_cpu_features (void)
/* Determine if AVX is usable. */
if (CPUID_AVX)
__cpu_features.feature[index_AVX_Usable] |= bit_AVX_Usable;
+ /* Determine if AVX2 is usable. */
+ if (CPUID_AVX2)
+ __cpu_features.feature[index_AVX2_Usable] |= bit_AVX2_Usable;
/* Determine if FMA is usable. */
if (CPUID_FMA)
__cpu_features.feature[index_FMA_Usable] |= bit_FMA_Usable;
diff --git a/sysdeps/x86_64/multiarch/init-arch.h b/sysdeps/x86_64/multiarch/init-arch.h
index 793707a..813b6de 100644
--- a/sysdeps/x86_64/multiarch/init-arch.h
+++ b/sysdeps/x86_64/multiarch/init-arch.h
@@ -24,6 +24,7 @@
#define bit_FMA_Usable (1 << 7)
#define bit_FMA4_Usable (1 << 8)
#define bit_Slow_SSE4_2 (1 << 9)
+#define bit_AVX2_Usable (1 << 10)
/* CPUID Feature flags. */
@@ -40,6 +41,7 @@
/* COMMON_CPUID_INDEX_7. */
#define bit_RTM (1 << 11)
+#define bit_AVX2 (1 << 5)
/* XCR0 Feature flags. */
#define bit_XMM_state (1 << 1)
@@ -54,6 +56,7 @@
# define index_SSE4_1 COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
# define index_SSE4_2 COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
# define index_AVX COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
+# define index_AVX2 COMMON_CPUID_INDEX_7*CPUID_SIZE+CPUID_EBX_OFFSET
# define index_Fast_Rep_String FEATURE_INDEX_1*FEATURE_SIZE
# define index_Fast_Copy_Backward FEATURE_INDEX_1*FEATURE_SIZE
@@ -64,6 +67,7 @@
# define index_FMA_Usable FEATURE_INDEX_1*FEATURE_SIZE
# define index_FMA4_Usable FEATURE_INDEX_1*FEATURE_SIZE
# define index_Slow_SSE4_2 FEATURE_INDEX_1*FEATURE_SIZE
+# define index_AVX2_Usable FEATURE_INDEX_1*FEATURE_SIZE
#else /* __ASSEMBLER__ */
@@ -145,6 +149,8 @@ extern const struct cpu_features *__get_cpu_features (void)
HAS_CPUID_FLAG (COMMON_CPUID_INDEX_80000001, ecx, bit_FMA4)
# define CPUID_RTM \
HAS_CPUID_FLAG (COMMON_CPUID_INDEX_7, ebx, bit_RTM)
+# define CPUID_AVX2 \
+ HAS_CPUID_FLAG (COMMON_CPUID_INDEX_7, ebx, bit_AVX2)
/* HAS_* evaluates to true if we may use the feature at runtime. */
# define HAS_SSE2 HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, edx, bit_SSE2)
@@ -153,6 +159,7 @@ extern const struct cpu_features *__get_cpu_features (void)
# define HAS_SSE4_1 HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_SSE4_1)
# define HAS_SSE4_2 HAS_CPU_FEATURE (COMMON_CPUID_INDEX_1, ecx, bit_SSE4_2)
# define HAS_RTM HAS_CPU_FEATURE (COMMON_CPUID_INDEX_7, ebx, bit_RTM)
+# define HAS_AVX2 HAS_CPU_FEATURE (COMMON_CPUID_INDEX_7, ebx, bit_AVX2)
# define index_Fast_Rep_String FEATURE_INDEX_1
# define index_Fast_Copy_Backward FEATURE_INDEX_1
@@ -163,6 +170,7 @@ extern const struct cpu_features *__get_cpu_features (void)
# define index_FMA_Usable FEATURE_INDEX_1
# define index_FMA4_Usable FEATURE_INDEX_1
# define index_Slow_SSE4_2 FEATURE_INDEX_1
+# define index_AVX2_Usable FEATURE_INDEX_1
# define HAS_ARCH_FEATURE(name) \
((__get_cpu_features ()->feature[index_##name] & (bit_##name)) != 0)
--
1.8.1.4