[dpdk-dev] [PATCH v2 2/3] app/testpmd: fix port topology in RSS fwd config

[Matan Azrad]

The testpmd user can configure port topology mode to define the port
topology between the testpmd forward ports(paired, chained and loop).

When multi-queue ports are configured by the user, the testpmd
streams are created by rss_fwd_config_setup() function, this function
doesn't take into account the chained topology mode and configures the
forward streams with paired topology mode in this case.

Configure the stream Tx port by dedicated function which calculates
a valid Tx port index as a function of the topology mode and the Rx
port index.

Fixes: af75078 ("first public release")
Cc: stable at dpdk.org

Signed-off-by: Matan Azrad <matan at mellanox.com>
---
 app/test-pmd/config.c | 49 +++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 3053b56..02ab1e3 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -1882,6 +1882,36 @@ struct igb_ring_desc_16_bytes {
 	}
 }
 
+static portid_t
+fwd_topology_tx_port_get(portid_t rxp)
+{
+	static int warning_once = 1;
+
+	RTE_ASSERT(rxp < cur_fwd_config.nb_fwd_ports);
+
+	switch (port_topology) {
+	default:
+	case PORT_TOPOLOGY_PAIRED:
+		if ((rxp & 0x1) == 0) {
+			if (rxp + 1 < cur_fwd_config.nb_fwd_ports)
+				return rxp + 1;
+			if (warning_once) {
+				printf("\nWarning! port-topology=paired"
+				       " and odd forward ports number,"
+				       " the last port will pair with"
+				       " itself.\n\n");
+				warning_once = 0;
+			}
+			return rxp;
+		}
+		return rxp - 1;
+	case PORT_TOPOLOGY_CHAINED:
+		return (rxp + 1) % cur_fwd_config.nb_fwd_ports;
+	case PORT_TOPOLOGY_LOOP:
+		return rxp;
+	}
+}
+
 static void
 simple_fwd_config_setup(void)
 {
@@ -1944,11 +1974,6 @@ struct igb_ring_desc_16_bytes {
  * For the RSS forwarding test all streams distributed over lcores. Each stream
  * being composed of a RX queue to poll on a RX port for input messages,
  * associated with a TX queue of a TX port where to send forwarded packets.
- * All packets received on the RX queue of index "RxQj" of the RX port "RxPi"
- * are sent on the TX queue "TxQl" of the TX port "TxPk" according to the two
- * following rules:
- *    - TxPk = (RxPi + 1) if RxPi is even, (RxPi - 1) if RxPi is odd
- *    - TxQl = RxQj
  */
 static void
 rss_fwd_config_setup(void)
@@ -1980,19 +2005,7 @@ struct igb_ring_desc_16_bytes {
 		struct fwd_stream *fs;
 
 		fs = fwd_streams[sm_id];
-
-		if ((rxp & 0x1) == 0)
-			txp = (portid_t) (rxp + 1);
-		else
-			txp = (portid_t) (rxp - 1);
-		/*
-		 * if we are in loopback, simply send stuff out through the
-		 * ingress port
-		 */
-		if (port_topology == PORT_TOPOLOGY_LOOP ||
-		    txp >= cur_fwd_config.nb_fwd_ports)
-			txp = rxp;
-
+		txp = fwd_topology_tx_port_get(rxp);
 		fs->rx_port = fwd_ports_ids[rxp];
 		fs->rx_queue = rxq;
 		fs->tx_port = fwd_ports_ids[txp];
-- 
1.8.3.1