[PATCH v8 4/4] hash: add SVE support for bulk key lookup

[Yoan Picchi <yoan.picchi@arm.com>]

- Implemented SVE code for comparing signatures in bulk lookup.
- New SVE code is ~5% slower than optimized NEON for N2 processor for
128b vectors.

Signed-off-by: Yoan Picchi <yoan.picchi@arm.com>
Signed-off-by: Harjot Singh <harjot.singh@arm.com>
Reviewed-by: Nathan Brown <nathan.brown@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 lib/hash/arch/arm/compare_signatures.h | 58 ++++++++++++++++++++++++++
 lib/hash/rte_cuckoo_hash.c             |  7 +++-
 lib/hash/rte_cuckoo_hash.h             |  1 +
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/lib/hash/arch/arm/compare_signatures.h b/lib/hash/arch/arm/compare_signatures.h
index 2601ed68b3..140ff97b1d 100644
--- a/lib/hash/arch/arm/compare_signatures.h
+++ b/lib/hash/arch/arm/compare_signatures.h
@@ -47,6 +47,64 @@ compare_signatures_dense(uint16_t *hitmask_buffer,
 		*hitmask_buffer = vaddvq_u16(hit2);
 		}
 		break;
+#endif
+#if defined(RTE_HAS_SVE_ACLE)
+	case RTE_HASH_COMPARE_SVE: {
+		svuint16_t vsign, shift, sv_matches;
+		svbool_t pred, match, bucket_wide_pred;
+		int i = 0;
+		uint64_t vl = svcnth();
+
+		vsign = svdup_u16(sig);
+		shift = svindex_u16(0, 1);
+
+		if (vl >= 2 * RTE_HASH_BUCKET_ENTRIES && RTE_HASH_BUCKET_ENTRIES <= 8) {
+			svuint16_t primary_array_vect, secondary_array_vect;
+			bucket_wide_pred = svwhilelt_b16(0, RTE_HASH_BUCKET_ENTRIES);
+			primary_array_vect = svld1_u16(bucket_wide_pred, prim_bucket_sigs);
+			secondary_array_vect = svld1_u16(bucket_wide_pred, sec_bucket_sigs);
+
+			/* We merged the two vectors so we can do both comparisons at once */
+			primary_array_vect = svsplice_u16(bucket_wide_pred,
+				primary_array_vect,
+				secondary_array_vect);
+			pred = svwhilelt_b16(0, 2*RTE_HASH_BUCKET_ENTRIES);
+
+			/* Compare all signatures in the buckets */
+			match = svcmpeq_u16(pred, vsign, primary_array_vect);
+			if (svptest_any(svptrue_b16(), match)) {
+				sv_matches = svdup_u16(1);
+				sv_matches = svlsl_u16_z(match, sv_matches, shift);
+				*hitmask_buffer = svorv_u16(svptrue_b16(), sv_matches);
+			}
+		} else {
+			do {
+				pred = svwhilelt_b16(i, RTE_HASH_BUCKET_ENTRIES);
+				uint16_t lower_half = 0;
+				uint16_t upper_half = 0;
+				/* Compare all signatures in the primary bucket */
+				match = svcmpeq_u16(pred, vsign, svld1_u16(pred,
+							&prim_bucket_sigs[i]));
+				if (svptest_any(svptrue_b16(), match)) {
+					sv_matches = svdup_u16(1);
+					sv_matches = svlsl_u16_z(match, sv_matches, shift);
+					lower_half = svorv_u16(svptrue_b16(), sv_matches);
+				}
+				/* Compare all signatures in the secondary bucket */
+				match = svcmpeq_u16(pred, vsign, svld1_u16(pred,
+							&sec_bucket_sigs[i]));
+				if (svptest_any(svptrue_b16(), match)) {
+					sv_matches = svdup_u16(1);
+					sv_matches = svlsl_u16_z(match, sv_matches, shift);
+					upper_half = svorv_u16(svptrue_b16(), sv_matches)
+						<< RTE_HASH_BUCKET_ENTRIES;
+				}
+				hitmask_buffer[i / 8] = upper_half | lower_half;
+				i += vl;
+			} while (i < RTE_HASH_BUCKET_ENTRIES);
+		}
+		}
+		break;
 #endif
 	default:
 		for (unsigned int i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 0697743cdf..75f555ba2c 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -450,8 +450,13 @@ rte_hash_create(const struct rte_hash_parameters *params)
 		h->sig_cmp_fn = RTE_HASH_COMPARE_SSE;
 	else
 #elif defined(RTE_ARCH_ARM64)
-	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON))
+	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON)) {
 		h->sig_cmp_fn = RTE_HASH_COMPARE_NEON;
+#if defined(RTE_HAS_SVE_ACLE)
+		if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SVE))
+			h->sig_cmp_fn = RTE_HASH_COMPARE_SVE;
+#endif
+	}
 	else
 #endif
 		h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
diff --git a/lib/hash/rte_cuckoo_hash.h b/lib/hash/rte_cuckoo_hash.h
index a528f1d1a0..01ad01c258 100644
--- a/lib/hash/rte_cuckoo_hash.h
+++ b/lib/hash/rte_cuckoo_hash.h
@@ -139,6 +139,7 @@ enum rte_hash_sig_compare_function {
 	RTE_HASH_COMPARE_SCALAR = 0,
 	RTE_HASH_COMPARE_SSE,
 	RTE_HASH_COMPARE_NEON,
+	RTE_HASH_COMPARE_SVE,
 	RTE_HASH_COMPARE_NUM
 };
 
-- 
2.25.1