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authorJohn McNamara <john.mcnamara@intel.com>2015-02-25 19:46:00 +0000
committerThomas Monjalon <thomas.monjalon@6wind.com>2015-03-17 22:16:46 +0100
commit0f91352cff9a793805f5144f9589ffe211876b34 (patch)
tree995b4114a0004b0ed8aa555591525b719210298a /examples/skeleton
parent37b786347c08062049982b89bb1d5552e4cef72b (diff)
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examples/skeleton: improve documentation
Minor refactoring and comments to make the sample app and code examples clearer for the sample app guide. Signed-off-by: John McNamara <john.mcnamara@intel.com> Acked-by: Siobhan Butler <siobhan.a.butler@intel.com> Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Diffstat (limited to 'examples/skeleton')
-rw-r--r--examples/skeleton/basicfwd.c77
1 files changed, 57 insertions, 20 deletions
diff --git a/examples/skeleton/basicfwd.c b/examples/skeleton/basicfwd.c
index 6aa931e..1bce6e7 100644
--- a/examples/skeleton/basicfwd.c
+++ b/examples/skeleton/basicfwd.c
@@ -1,7 +1,7 @@
/*-
* BSD LICENSE
*
- * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ * Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -48,12 +48,14 @@
#define BURST_SIZE 32
static const struct rte_eth_conf port_conf_default = {
- .rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN, },
+ .rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN }
};
+/* basicfwd.c: Basic DPDK skeleton forwarding example. */
+
/*
- * Initialises a given port using global settings and with the rx buffers
- * coming from the mbuf_pool passed as parameter
+ * Initializes a given port using global settings and with the RX buffers
+ * coming from the mbuf_pool passed as a parameter.
*/
static inline int
port_init(uint8_t port, struct rte_mempool *mbuf_pool)
@@ -66,10 +68,12 @@ port_init(uint8_t port, struct rte_mempool *mbuf_pool)
if (port >= rte_eth_dev_count())
return -1;
+ /* Configure the Ethernet device. */
retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
if (retval != 0)
return retval;
+ /* Allocate and set up 1 RX queue per Ethernet port. */
for (q = 0; q < rx_rings; q++) {
retval = rte_eth_rx_queue_setup(port, q, RX_RING_SIZE,
rte_eth_dev_socket_id(port), NULL, mbuf_pool);
@@ -77,6 +81,7 @@ port_init(uint8_t port, struct rte_mempool *mbuf_pool)
return retval;
}
+ /* Allocate and set up 1 TX queue per Ethernet port. */
for (q = 0; q < tx_rings; q++) {
retval = rte_eth_tx_queue_setup(port, q, TX_RING_SIZE,
rte_eth_dev_socket_id(port), NULL);
@@ -84,33 +89,41 @@ port_init(uint8_t port, struct rte_mempool *mbuf_pool)
return retval;
}
- retval = rte_eth_dev_start(port);
+ /* Start the Ethernet port. */
+ retval = rte_eth_dev_start(port);
if (retval < 0)
return retval;
+ /* Display the port MAC address. */
struct ether_addr addr;
rte_eth_macaddr_get(port, &addr);
- printf("Port %u MAC: %02"PRIx8" %02"PRIx8" %02"PRIx8
- " %02"PRIx8" %02"PRIx8" %02"PRIx8"\n",
+ printf("Port %u MAC: %02" PRIx8 " %02" PRIx8 " %02" PRIx8
+ " %02" PRIx8 " %02" PRIx8 " %02" PRIx8 "\n",
(unsigned)port,
addr.addr_bytes[0], addr.addr_bytes[1],
addr.addr_bytes[2], addr.addr_bytes[3],
addr.addr_bytes[4], addr.addr_bytes[5]);
+ /* Enable RX in promiscuous mode for the Ethernet device. */
rte_eth_promiscuous_enable(port);
return 0;
}
/*
- * Main thread that does the work, reading from INPUT_PORT
- * and writing to OUTPUT_PORT
+ * The lcore main. This is the main thread that does the work, reading from
+ * an input port and writing to an output port.
*/
-static __attribute__((noreturn)) void
+static __attribute__((noreturn)) void
lcore_main(void)
{
const uint8_t nb_ports = rte_eth_dev_count();
uint8_t port;
+
+ /*
+ * Check that the port is on the same NUMA node as the polling thread
+ * for best performance.
+ */
for (port = 0; port < nb_ports; port++)
if (rte_eth_dev_socket_id(port) > 0 &&
rte_eth_dev_socket_id(port) !=
@@ -121,15 +134,28 @@ lcore_main(void)
printf("\nCore %u forwarding packets. [Ctrl+C to quit]\n",
rte_lcore_id());
+
+ /* Run until the application is quit or killed. */
for (;;) {
+ /*
+ * Receive packets on a port and forward them on the paired
+ * port. The mapping is 0 -> 1, 1 -> 0, 2 -> 3, 3 -> 2, etc.
+ */
for (port = 0; port < nb_ports; port++) {
+
+ /* Get burst of RX packets, from first port of pair. */
struct rte_mbuf *bufs[BURST_SIZE];
const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
bufs, BURST_SIZE);
+
if (unlikely(nb_rx == 0))
continue;
+
+ /* Send burst of TX packets, to second port of pair. */
const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
bufs, nb_rx);
+
+ /* Free any unsent packets. */
if (unlikely(nb_tx < nb_rx)) {
uint16_t buf;
for (buf = nb_tx; buf < nb_rx; buf++)
@@ -139,7 +165,10 @@ lcore_main(void)
}
}
-/* Main function, does initialisation and calls the per-lcore functions */
+/*
+ * The main function, which does initialization and calls the per-lcore
+ * functions.
+ */
int
main(int argc, char *argv[])
{
@@ -147,36 +176,44 @@ main(int argc, char *argv[])
unsigned nb_ports;
uint8_t portid;
- /* init EAL */
+ /* Initialize the Environment Abstraction Layer (EAL). */
int ret = rte_eal_init(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
+
argc -= ret;
argv += ret;
+ /* Check that there is an even number of ports to send/receive on. */
nb_ports = rte_eth_dev_count();
if (nb_ports < 2 || (nb_ports & 1))
rte_exit(EXIT_FAILURE, "Error: number of ports must be even\n");
- mbuf_pool = rte_mempool_create("MBUF_POOL", NUM_MBUFS * nb_ports,
- MBUF_SIZE, MBUF_CACHE_SIZE,
+ /* Creates a new mempool in memory to hold the mbufs. */
+ mbuf_pool = rte_mempool_create("MBUF_POOL",
+ NUM_MBUFS * nb_ports,
+ MBUF_SIZE,
+ MBUF_CACHE_SIZE,
sizeof(struct rte_pktmbuf_pool_private),
rte_pktmbuf_pool_init, NULL,
- rte_pktmbuf_init, NULL,
- rte_socket_id(), 0);
+ rte_pktmbuf_init, NULL,
+ rte_socket_id(),
+ 0);
+
if (mbuf_pool == NULL)
rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
- /* initialize all ports */
+ /* Initialize all ports. */
for (portid = 0; portid < nb_ports; portid++)
if (port_init(portid, mbuf_pool) != 0)
- rte_exit(EXIT_FAILURE, "Cannot init port %"PRIu8"\n",
+ rte_exit(EXIT_FAILURE, "Cannot init port %"PRIu8 "\n",
portid);
if (rte_lcore_count() > 1)
- printf("\nWARNING: Too much enabled lcores - App uses only 1 lcore\n");
+ printf("\nWARNING: Too many lcores enabled. Only 1 used.\n");
- /* call lcore_main on master core only */
+ /* Call lcore_main on the master core only. */
lcore_main();
+
return 0;
}