[dpdk-dev] [PATCH v2 20/28] node: ipv4 lookup for x86

[<jerinj@marvell.com>]

From: Pavan Nikhilesh <pbhagavatula@marvell.com>

Add IPv4 lookup process function for ip4_lookup
rte_node. This node performs LPM lookup using x86_64
vector supported RTE_LPM API on every packet received
and forwards it to a next node that is identified by
lookup result.

Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Signed-off-by: Kiran Kumar K <kirankumark@marvell.com>
---
 lib/librte_node/ip4_lookup.c | 238 +++++++++++++++++++++++++++++++++++
 1 file changed, 238 insertions(+)

diff --git a/lib/librte_node/ip4_lookup.c b/lib/librte_node/ip4_lookup.c
index dddabc6c2..a9e204148 100644
--- a/lib/librte_node/ip4_lookup.c
+++ b/lib/librte_node/ip4_lookup.c
@@ -259,6 +259,244 @@ ip4_lookup_node_process(struct rte_graph *graph, struct rte_node *node,
 	return nb_objs;
 }
 
+#elif defined(RTE_ARCH_X86)
+
+/* X86 SSE */
+static uint16_t
+ip4_lookup_node_process(struct rte_graph *graph, struct rte_node *node,
+			void **objs, uint16_t nb_objs)
+{
+	struct rte_mbuf *mbuf0, *mbuf1, *mbuf2, *mbuf3, **pkts;
+	rte_edge_t next0, next1, next2, next3, next_index;
+	struct rte_ipv4_hdr *ipv4_hdr;
+	uint32_t ip0, ip1, ip2, ip3;
+	void **to_next, **from;
+	uint16_t last_spec = 0;
+	uint16_t n_left_from;
+	struct rte_lpm *lpm;
+	uint16_t held = 0;
+	uint32_t drop_nh;
+	rte_xmm_t dst;
+	__m128i dip; /* SSE register */
+	int rc, i;
+
+	/* Speculative next */
+	next_index = RTE_NODE_IP4_LOOKUP_NEXT_REWRITE;
+	/* Drop node */
+	drop_nh = ((uint32_t)RTE_NODE_IP4_LOOKUP_NEXT_PKT_DROP) << 16;
+
+	/* Get socket specific LPM from ctx */
+	lpm = *((struct rte_lpm **)node->ctx);
+
+	pkts = (struct rte_mbuf **)objs;
+	from = objs;
+	n_left_from = nb_objs;
+
+	if (n_left_from >= 4) {
+		for (i = 0; i < 4; i++)
+			rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[i], void *,
+						sizeof(struct rte_ether_hdr)));
+	}
+
+	/* Get stream for the speculated next node */
+	to_next = rte_node_next_stream_get(graph, node, next_index, nb_objs);
+	while (n_left_from >= 4) {
+		/* Prefetch next-next mbufs */
+		if (likely(n_left_from > 11)) {
+			rte_prefetch0(pkts[8]);
+			rte_prefetch0(pkts[9]);
+			rte_prefetch0(pkts[10]);
+			rte_prefetch0(pkts[11]);
+		}
+
+		/* Prefetch next mbuf data */
+		if (likely(n_left_from > 7)) {
+			rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[4], void *,
+						sizeof(struct rte_ether_hdr)));
+			rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[5], void *,
+						sizeof(struct rte_ether_hdr)));
+			rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[6], void *,
+						sizeof(struct rte_ether_hdr)));
+			rte_prefetch0(rte_pktmbuf_mtod_offset(pkts[7], void *,
+						sizeof(struct rte_ether_hdr)));
+		}
+
+		mbuf0 = pkts[0];
+		mbuf1 = pkts[1];
+		mbuf2 = pkts[2];
+		mbuf3 = pkts[3];
+
+		pkts += 4;
+		n_left_from -= 4;
+
+		/* Extract DIP of mbuf0 */
+		ipv4_hdr = rte_pktmbuf_mtod_offset(mbuf0, struct rte_ipv4_hdr *,
+						sizeof(struct rte_ether_hdr));
+		ip0 = ipv4_hdr->dst_addr;
+		/* Extract cksum, ttl as ipv4 hdr is in cache */
+		rte_node_mbuf_priv1(mbuf0)->cksum = ipv4_hdr->hdr_checksum;
+		rte_node_mbuf_priv1(mbuf0)->ttl = ipv4_hdr->time_to_live;
+
+		/* Extract DIP of mbuf1 */
+		ipv4_hdr = rte_pktmbuf_mtod_offset(mbuf1, struct rte_ipv4_hdr *,
+						sizeof(struct rte_ether_hdr));
+		ip1 = ipv4_hdr->dst_addr;
+		/* Extract cksum, ttl as ipv4 hdr is in cache */
+		rte_node_mbuf_priv1(mbuf1)->cksum = ipv4_hdr->hdr_checksum;
+		rte_node_mbuf_priv1(mbuf1)->ttl = ipv4_hdr->time_to_live;
+
+		/* Extract DIP of mbuf2 */
+		ipv4_hdr = rte_pktmbuf_mtod_offset(mbuf2, struct rte_ipv4_hdr *,
+						sizeof(struct rte_ether_hdr));
+		ip2 = ipv4_hdr->dst_addr;
+		/* Extract cksum, ttl as ipv4 hdr is in cache */
+		rte_node_mbuf_priv1(mbuf2)->cksum = ipv4_hdr->hdr_checksum;
+		rte_node_mbuf_priv1(mbuf2)->ttl = ipv4_hdr->time_to_live;
+
+		/* Extract DIP of mbuf3 */
+		ipv4_hdr = rte_pktmbuf_mtod_offset(mbuf3, struct rte_ipv4_hdr *,
+						sizeof(struct rte_ether_hdr));
+		ip3 = ipv4_hdr->dst_addr;
+
+		/* Prepare for lookup x4 */
+		dip = _mm_set_epi32(ip3, ip2, ip1, ip0);
+
+		/* Byte swap 4 IPV4 addresses. */
+		const __m128i bswap_mask = _mm_set_epi8(
+			12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3);
+		dip = _mm_shuffle_epi8(dip, bswap_mask);
+
+		/* Extract cksum, ttl as ipv4 hdr is in cache */
+		rte_node_mbuf_priv1(mbuf3)->cksum = ipv4_hdr->hdr_checksum;
+		rte_node_mbuf_priv1(mbuf3)->ttl = ipv4_hdr->time_to_live;
+
+		/* Perform LPM lookup to get NH and next node */
+		rte_lpm_lookupx4(lpm, dip, dst.u32, drop_nh);
+
+		/* Extract next node id and NH */
+		rte_node_mbuf_priv1(mbuf0)->nh = dst.u32[0] & 0xFFFF;
+		next0 = (dst.u32[0] >> 16);
+
+		rte_node_mbuf_priv1(mbuf1)->nh = dst.u32[1] & 0xFFFF;
+		next1 = (dst.u32[1] >> 16);
+
+		rte_node_mbuf_priv1(mbuf2)->nh = dst.u32[2] & 0xFFFF;
+		next2 = (dst.u32[2] >> 16);
+
+		rte_node_mbuf_priv1(mbuf3)->nh = dst.u32[3] & 0xFFFF;
+		next3 = (dst.u32[3] >> 16);
+
+		/* Enqueue four to next node */
+		rte_edge_t fix_spec =
+			(next_index ^ next0) | (next_index ^ next1) |
+			(next_index ^ next2) | (next_index ^ next3);
+
+		if (unlikely(fix_spec)) {
+			/* Copy things successfully speculated till now */
+			rte_memcpy(to_next, from, last_spec * sizeof(from[0]));
+			from += last_spec;
+			to_next += last_spec;
+			held += last_spec;
+			last_spec = 0;
+
+			/* Next0 */
+			if (next_index == next0) {
+				to_next[0] = from[0];
+				to_next++;
+				held++;
+			} else {
+				rte_node_enqueue_x1(graph, node, next0,
+						    from[0]);
+			}
+
+			/* Next1 */
+			if (next_index == next1) {
+				to_next[0] = from[1];
+				to_next++;
+				held++;
+			} else {
+				rte_node_enqueue_x1(graph, node, next1,
+						    from[1]);
+			}
+
+			/* Next2 */
+			if (next_index == next2) {
+				to_next[0] = from[2];
+				to_next++;
+				held++;
+			} else {
+				rte_node_enqueue_x1(graph, node, next2,
+						    from[2]);
+			}
+
+			/* Next3 */
+			if (next_index == next3) {
+				to_next[0] = from[3];
+				to_next++;
+				held++;
+			} else {
+				rte_node_enqueue_x1(graph, node, next3,
+						    from[3]);
+			}
+
+			from += 4;
+
+		} else {
+			last_spec += 4;
+		}
+	}
+
+	while (n_left_from > 0) {
+		uint32_t next_hop;
+
+		mbuf0 = pkts[0];
+
+		pkts += 1;
+		n_left_from -= 1;
+
+		/* Extract DIP of mbuf0 */
+		ipv4_hdr = rte_pktmbuf_mtod_offset(mbuf0, struct rte_ipv4_hdr *,
+						sizeof(struct rte_ether_hdr));
+		/* Extract cksum, ttl as ipv4 hdr is in cache */
+		rte_node_mbuf_priv1(mbuf0)->cksum = ipv4_hdr->hdr_checksum;
+		rte_node_mbuf_priv1(mbuf0)->ttl = ipv4_hdr->time_to_live;
+
+		rc = rte_lpm_lookup(lpm, rte_be_to_cpu_32(ipv4_hdr->dst_addr),
+				    &next_hop);
+		next_hop = (rc == 0) ? next_hop : drop_nh;
+
+		rte_node_mbuf_priv1(mbuf0)->nh = next_hop & 0xFFFF;
+		next0 = (next_hop >> 16);
+
+		if (unlikely(next_index ^ next0)) {
+			/* Copy things successfully speculated till now */
+			rte_memcpy(to_next, from, last_spec * sizeof(from[0]));
+			from += last_spec;
+			to_next += last_spec;
+			held += last_spec;
+			last_spec = 0;
+
+			rte_node_enqueue_x1(graph, node, next0, from[0]);
+			from += 1;
+		} else {
+			last_spec += 1;
+		}
+	}
+
+	/* !!! Home run !!! */
+	if (likely(last_spec == nb_objs)) {
+		rte_node_next_stream_move(graph, node, next_index);
+		return nb_objs;
+	}
+
+	held += last_spec;
+	/* Copy things successfully speculated till now */
+	rte_memcpy(to_next, from, last_spec * sizeof(from[0]));
+	rte_node_next_stream_put(graph, node, next_index, held);
+
+	return nb_objs;
+}
+
 #else
 
 static uint16_t
-- 
2.25.1