[dpdk-dev] [PATCH v4 1/5] efd: new Elastic Flow Distributor library

[De Lara Guarch, Pablo]

> -----Original Message-----
> From: Jerin Jacob [mailto:jerin.jacob at caviumnetworks.com]
> Sent: Monday, January 16, 2017 4:26 AM
> To: De Lara Guarch, Pablo
> Cc: dev at dpdk.org; Marohn, Byron; Edupuganti, Saikrishna
> Subject: Re: [dpdk-dev] [PATCH v4 1/5] efd: new Elastic Flow Distributor
> library
> 
> On Sun, Jan 15, 2017 at 12:04:31PM +0000, Pablo de Lara wrote:
> > Elastic Flow Distributor (EFD) is a distributor library that uses
> > perfect hashing to determine a target/value for a given incoming flow key.
> > It has the following advantages:
> >
> > - First, because it uses perfect hashing, it does not store
> >   the key itself and hence lookup performance is not dependent
> >   on the key size.
> >
> > - Second, the target/value can be any arbitrary value hence
> >   the system designer and/or operator can better optimize service rates
> >   and inter-cluster network traffic locating.
> >
> > - Third, since the storage requirement is much smaller than a hash-based
> >   flow table (i.e. better fit for CPU cache), EFD can scale to
> >   millions of flow keys.
> >   Finally, with current optimized library implementation performance
> >   is fully scalable with number of CPU cores.
> >
> > Signed-off-by: Byron Marohn <byron.marohn at intel.com>
> > Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
> > Signed-off-by: Saikrishna Edupuganti <saikrishna.edupuganti at intel.com>
> > Acked-by: Christian Maciocco <christian.maciocco at intel.com>
> > ---
> > +#if (RTE_EFD_VALUE_NUM_BITS == 8 || RTE_EFD_VALUE_NUM_BITS ==
> 16 || \
> > +	RTE_EFD_VALUE_NUM_BITS == 24 || RTE_EFD_VALUE_NUM_BITS
> == 32)
> > +#define EFD_LOAD_SI128(val) _mm_load_si128(val)
> > +#else
> > +#define EFD_LOAD_SI128(val) _mm_lddqu_si128(val)
> > +#endif
> > +
> > +static inline efd_value_t
> > +efd_lookup_internal(const struct efd_online_group_entry * const
> group,
> > +		const uint32_t hash_val_a, const uint32_t hash_val_b,
> > +		enum rte_efd_compare_function cmp_fn)
> > +{
> > +	efd_value_t value = 0;
> > +	uint32_t i;
> > +
> > +	switch (cmp_fn) {
> > +#ifdef RTE_MACHINE_CPUFLAG_AVX2
> > +	case RTE_HASH_COMPARE_AVX2:
> > +
> > +		i = 0;
> > +		__m256i vhash_val_a = _mm256_set1_epi32(hash_val_a);
> > +		__m256i vhash_val_b = _mm256_set1_epi32(hash_val_b);
> > +
> 
> Could you please abstract and move SIMD specific code to another file like
> other
> libraries(example: lib_acl) to enable smooth integration with neon and
> altivec
> SIMD implementations in future.

Sure, will modify it and send another version shortly.
Thanks,

Pablo
> 
> > +		for (; i < RTE_EFD_VALUE_NUM_BITS; i += 8) {
> > +			__m256i vhash_idx =
> > +
> 	_mm256_cvtepu16_epi32(EFD_LOAD_SI128(
> > +					(__m128i const *) &group-
> >hash_idx[i]));
> > +			__m256i vlookup_table =
> _mm256_cvtepu16_epi32(
> > +					EFD_LOAD_SI128((__m128i const *)
> > +					&group->lookup_table[i]));
> > +			__m256i vhash =
> _mm256_add_epi32(vhash_val_a,
> > +					_mm256_mullo_epi32(vhash_idx,
> vhash_val_b));
> > +			__m256i vbucket_idx = _mm256_srli_epi32(vhash,
> > +					EFD_LOOKUPTBL_SHIFT);
> > +			__m256i vresult =
> _mm256_srlv_epi32(vlookup_table,
> > +					vbucket_idx);
> > +
> > +			value |= (_mm256_movemask_ps(
> > +				(__m256) _mm256_slli_epi32(vresult, 31))
> > +				& ((1 << (RTE_EFD_VALUE_NUM_BITS - i)) -
> 1)) << i;
> > +		}
> > +		break;
> > +#endif