> -----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
