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.
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
