[dpdk-dev] [PATCH v2 3/3] efd: run-time dispatch over x86 EFD functions

[Xiaoyun Li <xiaoyun.li@intel.com>]

This patch dynamically selects x86 EFD functions at run-time.
This patch uses function pointer and binds it to the relative
function based on CPU flags at constructor time.

Signed-off-by: Xiaoyun Li <xiaoyun.li@intel.com>
---
 lib/librte_efd/rte_efd_x86.h | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/lib/librte_efd/rte_efd_x86.h b/lib/librte_efd/rte_efd_x86.h
index 34f37d7..93b6743 100644
--- a/lib/librte_efd/rte_efd_x86.h
+++ b/lib/librte_efd/rte_efd_x86.h
@@ -43,12 +43,29 @@
 #define EFD_LOAD_SI128(val) _mm_lddqu_si128(val)
 #endif
 
+typedef efd_value_t
+(*efd_lookup_internal_avx2_t)(const efd_hashfunc_t *group_hash_idx,
+		const efd_lookuptbl_t *group_lookup_table,
+		const uint32_t hash_val_a, const uint32_t hash_val_b);
+
+static efd_lookup_internal_avx2_t efd_lookup_internal_avx2_ptr;
+
 static inline efd_value_t
 efd_lookup_internal_avx2(const efd_hashfunc_t *group_hash_idx,
 		const efd_lookuptbl_t *group_lookup_table,
 		const uint32_t hash_val_a, const uint32_t hash_val_b)
 {
-#ifdef RTE_MACHINE_CPUFLAG_AVX2
+	return (*efd_lookup_internal_avx2_ptr)(group_hash_idx,
+					       group_lookup_table,
+					       hash_val_a, hash_val_b);
+}
+
+#ifdef CC_SUPPORT_AVX2
+static inline efd_value_t
+efd_lookup_internal_avx2_AVX2(const efd_hashfunc_t *group_hash_idx,
+		const efd_lookuptbl_t *group_lookup_table,
+		const uint32_t hash_val_a, const uint32_t hash_val_b)
+{
 	efd_value_t value = 0;
 	uint32_t i = 0;
 	__m256i vhash_val_a = _mm256_set1_epi32(hash_val_a);
@@ -74,13 +91,31 @@ efd_lookup_internal_avx2(const efd_hashfunc_t *group_hash_idx,
 	}
 
 	return value;
-#else
+}
+#endif
+
+static inline efd_value_t
+efd_lookup_internal_avx2_DEFAULT(const efd_hashfunc_t *group_hash_idx,
+		const efd_lookuptbl_t *group_lookup_table,
+		const uint32_t hash_val_a, const uint32_t hash_val_b)
+{
 	RTE_SET_USED(group_hash_idx);
 	RTE_SET_USED(group_lookup_table);
 	RTE_SET_USED(hash_val_a);
 	RTE_SET_USED(hash_val_b);
 	/* Return dummy value, only to avoid compilation breakage */
 	return 0;
-#endif
+}
 
+static void __attribute__((constructor))
+rte_efd_x86_init(void)
+{
+#ifdef CC_SUPPORT_AVX2
+	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2))
+		efd_lookup_internal_avx2_ptr = efd_lookup_internal_avx2_AVX2;
+	else
+		efd_lookup_internal_avx2_ptr = efd_lookup_internal_avx2_DEFAULT;
+#else
+	efd_lookup_internal_avx2_ptr = efd_lookup_internal_avx2_DEFAULT;
+#endif
 }
-- 
2.7.4