Re: [dpdk-dev] [EXT] [PATCH v1] hash: optimize signature compare by using neon intrinsic

[Jerin Jacob Kollanukkaran <jerinj@marvell.com>]

On Mon, 2019-02-11 at 15:30 +0800, Ruifeng Wang wrote:
> 
> -------------------------------------------------------------------
> ---
> Implemented signature compare function based on neon intrinsic.
> Hash bulk lookup had 3% - 6% performance gain after optimization.
> 
> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  lib/librte_hash/rte_cuckoo_hash.c | 32
> ++++++++++++++++++++++++++++++-
>  lib/librte_hash/rte_cuckoo_hash.h |  1 +
>  2 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
> b/lib/librte_hash/rte_cuckoo_hash.c
> index c01489ba5..5745a254f 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.c
> +++ b/lib/librte_hash/rte_cuckoo_hash.c
> @@ -26,6 +26,9 @@
>  #include <rte_spinlock.h>
>  #include <rte_ring.h>
>  #include <rte_compat.h>
> +#if defined(RTE_ARCH_ARM64)
> +#include <arm_neon.h>
> +#endif


The use of rte_vector.h will remove the need for #if defined...


>  
>  #include "rte_hash.h"
>  #include "rte_cuckoo_hash.h"
> @@ -407,6 +410,10 @@ rte_hash_create(const struct rte_hash_parameters
> *params)
>  	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE2))
>  		h->sig_cmp_fn = RTE_HASH_COMPARE_SSE;
>  	else
> +#elif defined(RTE_ARCH_ARM64)
> +	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON))
> +		h->sig_cmp_fn = RTE_HASH_COMPARE_NEON;
> +	else
>  #endif
>  		h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
>  
> @@ -1578,10 +1585,15 @@ compare_signatures(uint32_t
> *prim_hash_matches, uint32_t *sec_hash_matches,
>  			enum rte_hash_sig_compare_function sig_cmp_fn)
>  {
>  	unsigned int i;
> +#ifdef RTE_MACHINE_CPUFLAG_NEON
> +	uint16x8_t vmat, vsig, x;
> +	uint64x2_t x64;
> +	int16x8_t shift = {-15, -13, -11, -9, -7, -5, -3, -1};
> +#endif

Is it possible move down the variable declaration? to avoid the need
for #ifdef here

>  
>  	/* For match mask the first bit of every two bits indicates the
> match */
>  	switch (sig_cmp_fn) {
> -#ifdef RTE_MACHINE_CPUFLAG_SSE2
> +#if defined(RTE_MACHINE_CPUFLAG_SSE2)
>  	case RTE_HASH_COMPARE_SSE:
>  		/* Compare all signatures in the bucket */
>  		*prim_hash_matches = _mm_movemask_epi8(_mm_cmpeq_epi16(
> @@ -1594,6 +1606,24 @@ compare_signatures(uint32_t
> *prim_hash_matches, uint32_t *sec_hash_matches,
>  					(__m128i const *)sec_bkt-
> >sig_current),
>  				_mm_set1_epi16(sig)));
>  		break;
> +#elif defined(RTE_MACHINE_CPUFLAG_NEON)
> +	case RTE_HASH_COMPARE_NEON:
> +		vsig = vld1q_dup_u16((uint16_t const *)&sig);
> +		/* Compare all signatures in the primary bucket */
> +		vmat = vceqq_u16(vsig,
> +			vld1q_u16((uint16_t const *)prim_bkt-
> >sig_current));
> +		x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x8000)),
> shift);
> +		x64 = vpaddlq_u32(vpaddlq_u16(x));
> +		*prim_hash_matches = (uint32_t)(vgetq_lane_u64(x64, 0)
> +
> +			vgetq_lane_u64(x64, 1));
> +		/* Compare all signatures in the secondary bucket */
> +		vmat = vceqq_u16(vsig,
> +			vld1q_u16((uint16_t const *)sec_bkt-
> >sig_current));
> +		x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x8000)),
> shift);
> +		x64 = vpaddlq_u32(vpaddlq_u16(x));
> +		*sec_hash_matches = (uint32_t)(vgetq_lane_u64(x64, 0) +
> +			vgetq_lane_u64(x64, 1));
> +		break;
>  #endif
>  	default:
>  		for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
> diff --git a/lib/librte_hash/rte_cuckoo_hash.h
> b/lib/librte_hash/rte_cuckoo_hash.h
> index eacdaa8d4..0548c97f0 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.h
> +++ b/lib/librte_hash/rte_cuckoo_hash.h
> @@ -141,6 +141,7 @@ struct rte_hash_key {
>  enum rte_hash_sig_compare_function {
>  	RTE_HASH_COMPARE_SCALAR = 0,
>  	RTE_HASH_COMPARE_SSE,
> +	RTE_HASH_COMPARE_NEON,
>  	RTE_HASH_COMPARE_NUM
>  };
>