[dpdk-dev] [PATCH v3 3/3] efd: run-time dispatch over x86 EFD functions

Ananyev, Konstantin konstantin.ananyev at intel.com
Mon Oct 2 11:35:51 CEST 2017


> 
> >
> > This patch dynamically selects x86 EFD functions at run-time.
> 
> I don't think it really does.
> In fact, I am not sure that we need to touch EFD at all here -
> from what I can see, it already does dynamic selection properly.

Actually I was wrong here - in some cases it doesn't work properly.
As I can see for default target proper avx2 code wouldn't be compiled.
So some work still needed here - same as for memcpy().
Konstantin


> Konstantin
> 
> > 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 at 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



More information about the dev mailing list