[dpdk-dev] [PATCH] app/testpmd: fix txonly flow generation entropy

[Viacheslav Ovsiienko <viacheslavo@mellanox.com>]

The testpmd application in txonly forwarding mode has an option
to generate the packet flows by varying the destination IP address.
The patch increments the IP for each packet sent, this improves
the entropy and RSS distibution on the peer receiving size
is getting more uniform.

Fixes: 82010ef55e7c ("app/testpmd: make txonly mode generate multiple flows")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
 app/test-pmd/txonly.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/app/test-pmd/txonly.c b/app/test-pmd/txonly.c
index 4b5bec4..8a1989f 100644
--- a/app/test-pmd/txonly.c
+++ b/app/test-pmd/txonly.c
@@ -153,7 +153,6 @@
 		const uint16_t vlan_tci_outer, const uint64_t ol_flags)
 {
 	struct rte_mbuf *pkt_segs[RTE_MAX_SEGS_PER_PKT];
-	uint8_t  ip_var = RTE_PER_LCORE(_ip_var);
 	struct rte_mbuf *pkt_seg;
 	uint32_t nb_segs, pkt_len;
 	uint8_t i;
@@ -193,6 +192,7 @@
 	copy_buf_to_pkt(&pkt_ip_hdr, sizeof(pkt_ip_hdr), pkt,
 			sizeof(struct rte_ether_hdr));
 	if (txonly_multi_flow) {
+		uint8_t  ip_var = RTE_PER_LCORE(_ip_var);
 		struct rte_ipv4_hdr *ip_hdr;
 		uint32_t addr;
 
@@ -208,6 +208,7 @@
 		 */
 		addr = (tx_ip_dst_addr | (ip_var++ << 8)) + rte_lcore_id();
 		ip_hdr->src_addr = rte_cpu_to_be_32(addr);
+		RTE_PER_LCORE(_ip_var) = ip_var;
 	}
 	copy_buf_to_pkt(&pkt_udp_hdr, sizeof(pkt_udp_hdr), pkt,
 			sizeof(struct rte_ether_hdr) +
@@ -315,7 +316,7 @@
 	fs->tx_packets += nb_tx;
 
 	if (txonly_multi_flow)
-		RTE_PER_LCORE(_ip_var) += nb_tx;
+		RTE_PER_LCORE(_ip_var) -= nb_pkt - nb_tx;
 
 #ifdef RTE_TEST_PMD_RECORD_BURST_STATS
 	fs->tx_burst_stats.pkt_burst_spread[nb_tx]++;
-- 
1.8.3.1