[dpdk-dev] [PATCH v3] examples/l3fwd: em path performance fix

[Tomasz Kulasek]

It seems that for the most use cases, previous hash_multi_lookup provides
better performance, and more, sequential lookup can cause significant
performance drop.

This patch sets previously optional hash_multi_lookup method as default.
It also provides some minor optimizations such as queue drain only on used
tx ports.

v3 changes:
 - "lpm: extend IPv4 next hop field" patch extends dst_port table from
   uint16_t to uint32_t omiting previously disabled l3fwd_em_hlm_sse.h,
   what causes incompatible pointer type error after turning on this header

v2 changes:
 - fixed copy-paste error causing that not all packets are classified right
   in hash_multi_lookup implementation when burst size is not divisible
   by 8

Fixes: 94c54b4158d5 ("examples/l3fwd: rework exact-match")
Fixes: dc81ebbacaeb ("lpm: extend IPv4 next hop field")

Reported-by: Qian Xu <qian.q.xu at intel.com>
Signed-off-by: Tomasz Kulasek <tomaszx.kulasek at intel.com>
---
 examples/l3fwd/l3fwd.h            |    2 ++
 examples/l3fwd/l3fwd_em.c         |    6 +++---
 examples/l3fwd/l3fwd_em_hlm_sse.h |   34 +++++++++++++---------------------
 examples/l3fwd/l3fwd_em_sse.h     |    9 +++++++++
 examples/l3fwd/l3fwd_lpm.c        |    4 ++--
 examples/l3fwd/main.c             |    7 +++++++
 6 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/examples/l3fwd/l3fwd.h b/examples/l3fwd/l3fwd.h
index da6d369..207a60a 100644
--- a/examples/l3fwd/l3fwd.h
+++ b/examples/l3fwd/l3fwd.h
@@ -84,6 +84,8 @@ struct lcore_rx_queue {
 struct lcore_conf {
 	uint16_t n_rx_queue;
 	struct lcore_rx_queue rx_queue_list[MAX_RX_QUEUE_PER_LCORE];
+	uint16_t n_tx_port;
+	uint16_t tx_port_id[RTE_MAX_ETHPORTS];
 	uint16_t tx_queue_id[RTE_MAX_ETHPORTS];
 	struct mbuf_table tx_mbufs[RTE_MAX_ETHPORTS];
 	void *ipv4_lookup_struct;
diff --git a/examples/l3fwd/l3fwd_em.c b/examples/l3fwd/l3fwd_em.c
index f6a65d8..c8c781d 100644
--- a/examples/l3fwd/l3fwd_em.c
+++ b/examples/l3fwd/l3fwd_em.c
@@ -305,7 +305,7 @@ em_get_ipv6_dst_port(void *ipv6_hdr,  uint8_t portid, void *lookup_struct)
  * buffer optimization i.e. ENABLE_MULTI_BUFFER_OPTIMIZE=1.
  */
 #if defined(__SSE4_1__)
-#ifndef HASH_MULTI_LOOKUP
+#ifdef NO_HASH_MULTI_LOOKUP
 #include "l3fwd_em_sse.h"
 #else
 #include "l3fwd_em_hlm_sse.h"
@@ -552,8 +552,8 @@ em_main_loop(__attribute__((unused)) void *dummy)
 		diff_tsc = cur_tsc - prev_tsc;
 		if (unlikely(diff_tsc > drain_tsc)) {
 
-			for (i = 0; i < qconf->n_rx_queue; i++) {
-				portid = qconf->rx_queue_list[i].port_id;
+			for (i = 0; i < qconf->n_tx_port; ++i) {
+				portid = qconf->tx_port_id[i];
 				if (qconf->tx_mbufs[portid].len == 0)
 					continue;
 				send_burst(qconf,
diff --git a/examples/l3fwd/l3fwd_em_hlm_sse.h b/examples/l3fwd/l3fwd_em_hlm_sse.h
index d3388da..328dcb8 100644
--- a/examples/l3fwd/l3fwd_em_hlm_sse.h
+++ b/examples/l3fwd/l3fwd_em_hlm_sse.h
@@ -34,19 +34,11 @@
 #ifndef __L3FWD_EM_HLM_SSE_H__
 #define __L3FWD_EM_HLM_SSE_H__
 
-/**
- * @file
- * This is an optional implementation of packet classification in Exact-Match
- * path using rte_hash_lookup_multi method from previous implementation.
- * While sequential classification seems to be faster, it's disabled by default
- * and can be enabled with HASH_LOOKUP_MULTI global define in compilation time.
- */
-
 #include "l3fwd_sse.h"
 
-static inline void
+static inline __attribute__((always_inline)) void
 em_get_dst_port_ipv4x8(struct lcore_conf *qconf, struct rte_mbuf *m[8],
-		uint8_t portid, uint16_t dst_port[8])
+		uint8_t portid, uint32_t dst_port[8])
 {
 	int32_t ret[8];
 	union ipv4_5tuple_host key[8];
@@ -168,9 +160,9 @@ get_ipv6_5tuple(struct rte_mbuf *m0, __m128i mask0,
 	key->xmm[2] = _mm_and_si128(tmpdata2, mask1);
 }
 
-static inline void
+static inline __attribute__((always_inline)) void
 em_get_dst_port_ipv6x8(struct lcore_conf *qconf, struct rte_mbuf *m[8],
-		uint8_t portid, uint16_t dst_port[8])
+		uint8_t portid, uint32_t dst_port[8])
 {
 	int32_t ret[8];
 	union ipv6_5tuple_host key[8];
@@ -292,7 +284,7 @@ l3fwd_em_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
 		uint8_t portid, struct lcore_conf *qconf)
 {
 	int32_t j;
-	uint16_t dst_port[MAX_PKT_BURST];
+	uint32_t dst_port[MAX_PKT_BURST];
 
 	/*
 	 * Send nb_rx - nb_rx%8 packets
@@ -322,17 +314,17 @@ l3fwd_em_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
 
 		} else {
 			dst_port[j]   = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+1] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+2] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+3] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+4] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+5] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+6] = em_get_dst_port(qconf, pkts_burst[j], portid);
-			dst_port[j+7] = em_get_dst_port(qconf, pkts_burst[j], portid);
+			dst_port[j+1] = em_get_dst_port(qconf, pkts_burst[j+1], portid);
+			dst_port[j+2] = em_get_dst_port(qconf, pkts_burst[j+2], portid);
+			dst_port[j+3] = em_get_dst_port(qconf, pkts_burst[j+3], portid);
+			dst_port[j+4] = em_get_dst_port(qconf, pkts_burst[j+4], portid);
+			dst_port[j+5] = em_get_dst_port(qconf, pkts_burst[j+5], portid);
+			dst_port[j+6] = em_get_dst_port(qconf, pkts_burst[j+6], portid);
+			dst_port[j+7] = em_get_dst_port(qconf, pkts_burst[j+7], portid);
 		}
 	}
 
-	for (; j < n; j++)
+	for (; j < nb_rx; j++)
 		dst_port[j] = em_get_dst_port(qconf, pkts_burst[j], portid);
 
 	send_packets_multi(qconf, pkts_burst, dst_port, nb_rx);
diff --git a/examples/l3fwd/l3fwd_em_sse.h b/examples/l3fwd/l3fwd_em_sse.h
index d4a2a2d..8bd150a 100644
--- a/examples/l3fwd/l3fwd_em_sse.h
+++ b/examples/l3fwd/l3fwd_em_sse.h
@@ -34,6 +34,15 @@
 #ifndef __L3FWD_EM_SSE_H__
 #define __L3FWD_EM_SSE_H__
 
+/**
+ * @file
+ * This is an optional implementation of packet classification in Exact-Match
+ * path using sequential packet classification method.
+ * While hash lookup multi seems to provide better performance, it's disabled
+ * by default and can be enabled with NO_HASH_LOOKUP_MULTI global define in
+ * compilation time.
+ */
+
 #include "l3fwd_sse.h"
 
 static inline __attribute__((always_inline)) uint16_t
diff --git a/examples/l3fwd/l3fwd_lpm.c b/examples/l3fwd/l3fwd_lpm.c
index a354797..990a7f1 100644
--- a/examples/l3fwd/l3fwd_lpm.c
+++ b/examples/l3fwd/l3fwd_lpm.c
@@ -159,8 +159,8 @@ lpm_main_loop(__attribute__((unused)) void *dummy)
 		diff_tsc = cur_tsc - prev_tsc;
 		if (unlikely(diff_tsc > drain_tsc)) {
 
-			for (i = 0; i < qconf->n_rx_queue; i++) {
-				portid = qconf->rx_queue_list[i].port_id;
+			for (i = 0; i < qconf->n_tx_port; ++i) {
+				portid = qconf->tx_port_id[i];
 				if (qconf->tx_mbufs[portid].len == 0)
 					continue;
 				send_burst(qconf,
diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
index 0e33039..130817c 100644
--- a/examples/l3fwd/main.c
+++ b/examples/l3fwd/main.c
@@ -791,6 +791,7 @@ main(int argc, char **argv)
 	unsigned lcore_id;
 	uint32_t n_tx_queue, nb_lcores;
 	uint8_t portid, nb_rx_queue, queue, socketid;
+	uint8_t nb_tx_port;
 
 	/* init EAL */
 	ret = rte_eal_init(argc, argv);
@@ -830,6 +831,7 @@ main(int argc, char **argv)
 		rte_exit(EXIT_FAILURE, "check_port_config failed\n");
 
 	nb_lcores = rte_lcore_count();
+	nb_tx_port = 0;
 
 	/* Setup function pointers for lookup method. */
 	setup_l3fwd_lookup_tables();
@@ -906,8 +908,13 @@ main(int argc, char **argv)
 			qconf = &lcore_conf[lcore_id];
 			qconf->tx_queue_id[portid] = queueid;
 			queueid++;
+
+			qconf->n_tx_port = nb_tx_port;
+			qconf->tx_port_id[qconf->n_tx_port] = portid;
 		}
 		printf("\n");
+
+		nb_tx_port++;
 	}
 
 	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
-- 
1.7.9.5