hash: simplify signature compare with NEON

Replaced multiple neon instructions with single equivalent instruction.
This made simpler code and a bit higher performance.
Hash bulk lookup had 0.1% ~ 3% performance gain in tests on ARM A72
platforms.

Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Acked-by: Yipeng Wang <yipeng1.wang@intel.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>

diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 2dc423f..953928f 100644 (file)
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -1661,7 +1661,6 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 #elif defined(RTE_MACHINE_CPUFLAG_NEON)
        case RTE_HASH_COMPARE_NEON: {
                uint16x8_t vmat, vsig, x;
-               uint64x2_t x64;
                int16x8_t shift = {-15, -13, -11, -9, -7, -5, -3, -1};
 
                vsig = vld1q_dup_u16((uint16_t const *)&sig);
@@ -1669,16 +1668,13 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
                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));
+               *prim_hash_matches = (uint32_t)(vaddvq_u16(x));
                /* 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)); }
+               *sec_hash_matches = (uint32_t)(vaddvq_u16(x));
+               }
                break;
 #endif
        default: