Increase default mbuf size and code simplification/cleanup

mbuf size was setup to achieve the best performance i.e.
using the smallest mbuf and not segmenting packets.
However this resulted in complex code, much dependent of the way
the pmd are working e.g. a change(fix) in recent dpdk i40e
implementation caused a 1782 (=1518+8+256) bytes mbuf to be too
small to hold a 1518 bytes packets.
Hence this change simplifies the mbuf size selection at the price
of a potential decreases in performance - as more memory is now used.
Except if jumbo frames are used, the mbuf size will now be the same
for all modes. The packets will not be segmented except if jumbo
frames are enabled.
If jumbo frames are enabled, packets are by default segmented, except
if the mbuf size is configured big enough in the config file.

Change-Id: I222fcac7a65c0d221d5d422f419deb9c0f864172
Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>
Signed-off-by: Deepak S <deepak.s@linux.intel.com>

1 files changed, 41 insertions, 41 deletions

diff --git a/VNFs/DPPD-PROX/main.c b/VNFs/DPPD-PROX/main.c
index 59a169d8..2e1616af 100644
--- a/VNFs/DPPD-PROX/main.c
+++ b/VNFs/DPPD-PROX/main.c
@@ -252,10 +252,6 @@ static void configure_if_tx_queues(struct task_args *targ, uint8_t socket)
 		   use refcnt. */
 		if (!chain_flag_state(targ, TASK_FEATURE_TXQ_FLAGS_REFCOUNT, 1)) {
 			prox_port_cfg[if_port].tx_conf.txq_flags |= ETH_TXQ_FLAGS_NOREFCOUNT;
-			plog_info("\t\tEnabling No refcnt on port %d\n", if_port);
-		}
-		else {
-			plog_info("\t\tRefcnt used on port %d\n", if_port);
 		}
 
 		/* By default OFFLOAD is enabled, but if the whole
@@ -264,22 +260,8 @@ static void configure_if_tx_queues(struct task_args *targ, uint8_t socket)
 		   disabled for the destination port. */
 		if (!chain_flag_state(targ, TASK_FEATURE_TXQ_FLAGS_NOOFFLOADS, 0)) {
 			prox_port_cfg[if_port].tx_conf.txq_flags |= ETH_TXQ_FLAGS_NOOFFLOADS;
-			plog_info("\t\tDisabling TX offloads on port %d\n", if_port);
-		} else {
-			plog_info("\t\tEnabling TX offloads on port %d\n", if_port);
 		}
 
-		/* By default NOMULTSEGS is disabled, as drivers/NIC might split packets on RX
-		   It should only be enabled when we know for sure that the RX does not split packets.
-		   Set the ETH_TXQ_FLAGS_NOMULTSEGS flag if all of the tasks up to the task
-		   transmitting to the port use no_multsegs. */
-		if (!chain_flag_state(targ, TASK_FEATURE_TXQ_FLAGS_NOMULTSEGS, 0)) {
-			prox_port_cfg[if_port].tx_conf.txq_flags |= ETH_TXQ_FLAGS_NOMULTSEGS;
-			plog_info("\t\tEnabling No MultiSegs on port %d\n", if_port);
-		}
-		else {
-			plog_info("\t\tMultiSegs used on port %d\n", if_port);
-		}
 	}
 }
 
@@ -293,32 +275,50 @@ static void configure_if_rx_queues(struct task_args *targ, uint8_t socket)
 			return;
 		}
 
-		PROX_PANIC(!prox_port_cfg[if_port].active, "Port %u not used, aborting...\n", if_port);
 		port = &prox_port_cfg[if_port];
+		PROX_PANIC(!port->active, "Port %u not used, aborting...\n", if_port);
 
 		if(port->rx_ring[0] != '\0') {
 			port->n_rxq = 0;
 		}
 
-		// Force multi segment support if mbuf size is not big enough.
+		// If the mbuf size (of the rx task) is not big enough, we might receive multiple segments
 		// This is usually the case when setting a big mtu size i.e. enabling jumbo frames.
+		// If the packets get transmitted, then multi segments will have to be enabled on the TX port
 		uint16_t max_frame_size = port->mtu + ETHER_HDR_LEN + ETHER_CRC_LEN + 2 * PROX_VLAN_TAG_SIZE;
 		if (max_frame_size + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM > targ->mbuf_size) {
-			targ->task_init->flag_features &= ~TASK_FEATURE_TXQ_FLAGS_NOMULTSEGS;
-			plog_info("\t\tDisabling No MultSegs on port %u as %lu > %u\n", if_port, max_frame_size + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM, targ->mbuf_size);
+			targ->task_init->flag_features |= TASK_FEATURE_TXQ_FLAGS_MULTSEGS;
 		}
-		targ->rx_port_queue[i].queue = prox_port_cfg[if_port].n_rxq;
+		targ->rx_port_queue[i].queue = port->n_rxq;
 		port->pool[targ->rx_port_queue[i].queue] = targ->pool;
 		port->pool_size[targ->rx_port_queue[i].queue] = targ->nb_mbuf - 1;
 		port->n_rxq++;
 
-		int dsocket = prox_port_cfg[if_port].socket;
+		int dsocket = port->socket;
 		if (dsocket != -1 && dsocket != socket) {
 			plog_warn("RX core on socket %d while device on socket %d\n", socket, dsocket);
 		}
 	}
 }
 
+static void configure_multi_segments(void)
+{
+	struct lcore_cfg *lconf = NULL;
+	struct task_args *targ;
+	uint8_t if_port;
+
+	while (core_targ_next(&lconf, &targ, 0) == 0) {
+		for (uint8_t i = 0; i < targ->nb_txports; ++i) {
+			if_port = targ->tx_port_queue[i].port;
+			// Multi segment is disabled for most tasks. It is only enabled for tasks requiring big packets.
+			// We can only enable "no multi segment" if no such task exists in the chain of tasks.
+			if (!chain_flag_state(targ, TASK_FEATURE_TXQ_FLAGS_MULTSEGS, 1)) {
+				prox_port_cfg[if_port].tx_conf.txq_flags |= ETH_TXQ_FLAGS_NOMULTSEGS;
+			}
+		}
+	}
+}
+
 static void configure_if_queues(void)
 {
 	struct lcore_cfg *lconf = NULL;
@@ -591,20 +591,16 @@ static void set_mbuf_size(struct task_args *targ)
 {
 	/* mbuf size can be set
 	 *  - from config file (highest priority, overwriting any other config) - should only be used as workaround
-	 *  - through each 'mode', overwriting the default mbuf_size
-	 *  - defaulted to MBUF_SIZE i.e. 1518 Bytes
+	 *  - defaulted to MBUF_SIZE.
 	 * Except if set explicitely, ensure that size is big enough for vmxnet3 driver
 	 */
-	if (targ->mbuf_size_set_explicitely)
+	if (targ->mbuf_size)
 		return;
 
-	if (targ->task_init->mbuf_size != 0) {
-		/* mbuf_size not set through config file but set through mode */
-		targ->mbuf_size = targ->task_init->mbuf_size;
-	}
-
+	targ->mbuf_size = MBUF_SIZE;
 	struct prox_port_cfg *port;
-	uint16_t max_frame_size = 0;
+	uint16_t max_frame_size = 0, min_buffer_size = 0;
+	int i40e = 0;
 	for (int i = 0; i < targ->nb_rxports; i++) {
 		uint8_t if_port = targ->rx_port_queue[i].port;
 
@@ -614,22 +610,24 @@ static void set_mbuf_size(struct task_args *targ)
 		port = &prox_port_cfg[if_port];
 		if (max_frame_size < port->mtu + ETHER_HDR_LEN + ETHER_CRC_LEN + 2 * PROX_VLAN_TAG_SIZE)
 			max_frame_size = port->mtu + ETHER_HDR_LEN + ETHER_CRC_LEN + 2 * PROX_VLAN_TAG_SIZE;
+		if (min_buffer_size < port->min_rx_bufsize)
+			min_buffer_size = port->min_rx_bufsize;
 
-		if (strcmp(port->short_name, "vmxnet3") == 0) {
-			if (targ->mbuf_size < MBUF_SIZE + RTE_PKTMBUF_HEADROOM)
-				targ->mbuf_size = MBUF_SIZE + RTE_PKTMBUF_HEADROOM;
-			if (targ->mbuf_size < max_frame_size)
-				targ->mbuf_size = max_frame_size + RTE_PKTMBUF_HEADROOM;
-		}
+		// Check whether we receive from i40e. This driver have extra mbuf size requirements
+		if (strcmp(port->short_name, "i40e") == 0)
+			i40e = 1;
 	}
-	if (max_frame_size) {
+	if (i40e) {
 		// i40e supports a maximum of 5 descriptors chained
 		uint16_t required_mbuf_size = RTE_ALIGN(max_frame_size / 5, 128) + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM;
 		if (required_mbuf_size > targ->mbuf_size) {
 			targ->mbuf_size = required_mbuf_size;
-			plog_info("\t\tSetting mbuf_size to %u to support frame_size %u (mtu %u)\n", targ->mbuf_size, max_frame_size, port->mtu);
+			plog_info("\t\tSetting mbuf_size to %u to support frame_size %u\n", targ->mbuf_size, max_frame_size);
 		}
 	}
+	if (min_buffer_size > targ->mbuf_size) {
+		plog_warn("Mbuf size might be too small. This might result in packet segmentation and memory leak\n");
+	}
 
 }
 
@@ -915,6 +913,8 @@ static void init_lcores(void)
 	plog_info("=== Initializing queue numbers on cores ===\n");
 	configure_if_queues();
 
+	configure_multi_segments();
+
 	plog_info("=== Initializing rings on cores ===\n");
 	init_rings();