> -----Original Message----- > From: Li, Xiaoyun > Sent: Tuesday, October 3, 2017 9:15 AM > To: Ananyev, Konstantin <konstantin.anan...@intel.com>; Richardson, Bruce > <bruce.richard...@intel.com> > Cc: Lu, Wenzhuo <wenzhuo...@intel.com>; Zhang, Helin <helin.zh...@intel.com>; > dev@dpdk.org > Subject: RE: [PATCH v4 3/3] efd: run-time dispatch over x86 EFD functions > > Hi > > > -----Original Message----- > > From: Ananyev, Konstantin > > Sent: Tuesday, October 3, 2017 00:52 > > To: Li, Xiaoyun <xiaoyun...@intel.com>; Richardson, Bruce > > <bruce.richard...@intel.com> > > Cc: Lu, Wenzhuo <wenzhuo...@intel.com>; Zhang, Helin > > <helin.zh...@intel.com>; dev@dpdk.org > > Subject: RE: [PATCH v4 3/3] efd: run-time dispatch over x86 EFD functions > > > > > > > > > -----Original Message----- > > > From: Li, Xiaoyun > > > Sent: Monday, October 2, 2017 5:13 PM > > > To: Ananyev, Konstantin <konstantin.anan...@intel.com>; Richardson, > > > Bruce <bruce.richard...@intel.com> > > > Cc: Lu, Wenzhuo <wenzhuo...@intel.com>; Zhang, Helin > > > <helin.zh...@intel.com>; dev@dpdk.org; Li, Xiaoyun > > > <xiaoyun...@intel.com> > > > Subject: [PATCH v4 3/3] efd: run-time dispatch over x86 EFD functions > > > > > > 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...@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); > > > > I don't think you need all that. > > All you need - build proper avx2 function even if current HW doesn't support > > it. > > The existing runtime selection here seems ok already. > > Konstantin > > > > Sorry, not quite understand here. So don't need to change codes of efd here? > I didn't care about the HW. CC_SUPPORT_AVX2 only means the compiler supports > AVX2 since would runtime selection. > The existing codes RTE_MACHINE_CPUFLAG_AVX2 means both the compiler and HW > supports AVX2.
What I am saying - you don't need all these dances with extra function pointer. All you need - move efd_lookup_internal_avx2() into a .c file and make sure it get compiled with -mavx2 flag. Then at rte_efd_create() select AVX2 only when both HW and compiler supports AVX2: ... #ifdef CC_SUPPORT_AVX2 if (RTE_EFD_VALUE_NUM_BITS > 3 && rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2)) table->lookup_fn = EFD_LOOKUP_AVX2; else #endif ... Konstantin > > > Best Regards, > Xiaoyun Li > > > > > +} > > > + > > > +#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