[dpdk-dev] [PATCH v2 2/5] hash: enable gfni thash implementation

[Vladimir Medvedkin <vladimir.medvedkin@intel.com>]

This patch enables new GFNI Toeplitz hash in
predictable RSS library.

Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
---
 lib/hash/rte_thash.c | 44 ++++++++++++++++++++++++++++++++++++++++----
 lib/hash/rte_thash.h | 19 +++++++++++++++++++
 lib/hash/version.map |  1 +
 3 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/lib/hash/rte_thash.c b/lib/hash/rte_thash.c
index 59a8b8e..1f1d0cd 100644
--- a/lib/hash/rte_thash.c
+++ b/lib/hash/rte_thash.c
@@ -88,6 +88,8 @@ struct rte_thash_ctx {
 	uint32_t	reta_sz_log;	/** < size of the RSS ReTa in bits */
 	uint32_t	subtuples_nb;	/** < number of subtuples */
 	uint32_t	flags;
+	uint64_t	*matrices;
+	/**< matrices used with rte_thash_gfni implementation */
 	uint8_t		hash_key[0];
 };
 
@@ -256,12 +258,30 @@ rte_thash_init_ctx(const char *name, uint32_t key_len, uint32_t reta_sz,
 			ctx->hash_key[i] = rte_rand();
 	}
 
+	if (rte_thash_gfni_supported &&
+			(rte_vect_get_max_simd_bitwidth() >=
+			RTE_VECT_SIMD_512)) {
+		ctx->matrices = rte_zmalloc(NULL, key_len * sizeof(uint64_t),
+			RTE_CACHE_LINE_SIZE);
+		if (ctx->matrices == NULL) {
+			RTE_LOG(ERR, HASH, "Cannot allocate matrices\n");
+			rte_errno = ENOMEM;
+			goto free_ctx;
+		}
+
+		rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
+			key_len);
+	}
+
 	te->data = (void *)ctx;
 	TAILQ_INSERT_TAIL(thash_list, te, next);
 
 	rte_mcfg_tailq_write_unlock();
 
 	return ctx;
+
+free_ctx:
+	rte_free(ctx);
 free_te:
 	rte_free(te);
 exit:
@@ -375,6 +395,10 @@ generate_subkey(struct rte_thash_ctx *ctx, struct thash_lfsr *lfsr,
 			set_bit(ctx->hash_key, get_rev_bit_lfsr(lfsr), i);
 	}
 
+	if (ctx->matrices != NULL)
+		rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
+			ctx->key_len);
+
 	return 0;
 }
 
@@ -631,6 +655,12 @@ rte_thash_get_key(struct rte_thash_ctx *ctx)
 	return ctx->hash_key;
 }
 
+const uint64_t *
+rte_thash_get_gfni_matrices(struct rte_thash_ctx *ctx)
+{
+	return ctx->matrices;
+}
+
 static inline uint8_t
 read_unaligned_byte(uint8_t *ptr, unsigned int len, unsigned int offset)
 {
@@ -742,11 +772,17 @@ rte_thash_adjust_tuple(struct rte_thash_ctx *ctx,
 	attempts = RTE_MIN(attempts, 1U << (h->tuple_len - ctx->reta_sz_log));
 
 	for (i = 0; i < attempts; i++) {
-		for (j = 0; j < (tuple_len / 4); j++)
-			tmp_tuple[j] =
-				rte_be_to_cpu_32(*(uint32_t *)&tuple[j * 4]);
+		if (ctx->matrices != NULL)
+			hash = rte_thash_gfni(ctx->matrices, tuple, tuple_len);
+		else {
+			for (j = 0; j < (tuple_len / 4); j++)
+				tmp_tuple[j] =
+					rte_be_to_cpu_32(
+						*(uint32_t *)&tuple[j * 4]);
+
+			hash = rte_softrss(tmp_tuple, tuple_len / 4, hash_key);
+		}
 
-		hash = rte_softrss(tmp_tuple, tuple_len / 4, hash_key);
 		adj_bits = rte_thash_get_complement(h, hash, desired_value);
 
 		/*
diff --git a/lib/hash/rte_thash.h b/lib/hash/rte_thash.h
index e4f14a5..7afd359 100644
--- a/lib/hash/rte_thash.h
+++ b/lib/hash/rte_thash.h
@@ -412,6 +412,25 @@ const uint8_t *
 rte_thash_get_key(struct rte_thash_ctx *ctx);
 
 /**
+ * Get a pointer to the toeplitz hash matrices contained in the context.
+ * These matrices could be used with fast toeplitz hash implementation if
+ * CPU supports GFNI.
+ * Matrices changes after each addition of a helper.
+ *
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * @param ctx
+ *  Thash context
+ * @return
+ *  A pointer to the toeplitz hash key matrices on success
+ *  NULL if GFNI is not supported.
+ */
+__rte_experimental
+const uint64_t *
+rte_thash_get_gfni_matrices(struct rte_thash_ctx *ctx);
+
+/**
  * Function prototype for the rte_thash_adjust_tuple
  * to check if adjusted tuple could be used.
  * Generally it is some kind of lookup function to check
diff --git a/lib/hash/version.map b/lib/hash/version.map
index cecf922..3eda695 100644
--- a/lib/hash/version.map
+++ b/lib/hash/version.map
@@ -43,6 +43,7 @@ EXPERIMENTAL {
 	rte_thash_find_existing;
 	rte_thash_free_ctx;
 	rte_thash_get_complement;
+	rte_thash_get_gfni_matrices;
 	rte_thash_get_helper;
 	rte_thash_get_key;
 	rte_thash_gfni_supported;
-- 
2.7.4