dpdk l2fwd 应用流程分析
Posted jhcelue
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int
MAIN(int argc, char **argv)
{
struct lcore_queue_conf *qconf;
struct rte_eth_dev_info dev_info;
int ret;
uint8_t nb_ports;
uint8_t nb_ports_available;
uint8_t portid, last_port;
unsigned lcore_id, rx_lcore_id;
unsigned nb_ports_in_mask = 0;
/* init EAL */
ret = rte_eal_init(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid EAL arguments\n");
argc -= ret;
argv += ret;
/* parse application arguments (after the EAL ones) */
ret = l2fwd_parse_args(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid L2FWD arguments\n");
/* create the mbuf pool */
l2fwd_pktmbuf_pool =
rte_mempool_create("mbuf_pool", NB_MBUF,
MBUF_SIZE, 32,
sizeof(struct rte_pktmbuf_pool_private),
rte_pktmbuf_pool_init, NULL,
rte_pktmbuf_init, NULL,
rte_socket_id(), 0);
if (l2fwd_pktmbuf_pool == NULL)
rte_exit(EXIT_FAILURE, "Cannot init mbuf pool\n");
/* init driver(s) */
if (rte_pmd_init_all() < 0)
rte_exit(EXIT_FAILURE, "Cannot init pmd\n");
if (rte_eal_pci_probe() < 0)
rte_exit(EXIT_FAILURE, "Cannot probe PCI\n");
nb_ports = rte_eth_dev_count();
if (nb_ports == 0)
rte_exit(EXIT_FAILURE, "No Ethernet ports - bye\n");
if (nb_ports > RTE_MAX_ETHPORTS)
nb_ports = RTE_MAX_ETHPORTS;
/* reset l2fwd_dst_ports */
for (portid = 0; portid < RTE_MAX_ETHPORTS; portid++)
l2fwd_dst_ports[portid] = 0;
last_port = 0;
/* port0发给port1, port1发给port0. 两个端口为一对,互相发包 */
/*
* Each logical core is assigned a dedicated TX queue on each port.
*/
for (portid = 0; portid < nb_ports; portid++) {
/* skip ports that are not enabled */
if ((l2fwd_enabled_port_mask & (1 << portid)) == 0)
continue;
if (nb_ports_in_mask % 2) {
l2fwd_dst_ports[portid] = last_port;
l2fwd_dst_ports[last_port] = portid;
}
else
last_port = portid;
nb_ports_in_mask++;
rte_eth_dev_info_get(portid, &dev_info);
}
if (nb_ports_in_mask % 2) {
printf("Notice: odd number of ports in portmask.\n");
l2fwd_dst_ports[last_port] = last_port;
}
rx_lcore_id = 0;
qconf = NULL;
/* 每一个core负责收l2fwd_rx_queue_per_lcore个端口, 每一个端口(事实上应该是QUEUE,由于这里一个port仅仅有一个QUEUE)仅仅能由一个lcore进行收包 */
/* Initialize the port/queue configuration of each logical core */
for (portid = 0; portid < nb_ports; portid++) {
/* skip ports that are not enabled */
if ((l2fwd_enabled_port_mask & (1 << portid)) == 0)
continue;
/* get the lcore_id for this port */
while (rte_lcore_is_enabled(rx_lcore_id) == 0 ||
lcore_queue_conf[rx_lcore_id].n_rx_port ==
l2fwd_rx_queue_per_lcore) {
rx_lcore_id++;
if (rx_lcore_id >= RTE_MAX_LCORE)
rte_exit(EXIT_FAILURE, "Not enough cores\n");
}
if (qconf != &lcore_queue_conf[rx_lcore_id])
/* Assigned a new logical core in the loop above. */
qconf = &lcore_queue_conf[rx_lcore_id];
qconf->rx_port_list[qconf->n_rx_port] = portid;
qconf->n_rx_port++;
printf("Lcore %u: RX port %u\n", rx_lcore_id, (unsigned) portid);
}
nb_ports_available = nb_ports;
/* 每一个port收发包队列的初始化 */
/* Initialise each port */
for (portid = 0; portid < nb_ports; portid++) {
/* skip ports that are not enabled */
if ((l2fwd_enabled_port_mask & (1 << portid)) == 0) {
printf("Skipping disabled port %u\n", (unsigned) portid);
nb_ports_available--;
continue;
}
/* init port */
printf("Initializing port %u... ", (unsigned) portid);
fflush(stdout);
ret = rte_eth_dev_configure(portid, 1, 1, &port_conf);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Cannot configure device: err=%d, port=%u\n",
ret, (unsigned) portid);
rte_eth_macaddr_get(portid,&l2fwd_ports_eth_addr[portid]);
/* init one RX queue */
fflush(stdout);
ret = rte_eth_rx_queue_setup(portid, 0, nb_rxd,
rte_eth_dev_socket_id(portid), &rx_conf,
l2fwd_pktmbuf_pool);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_rx_queue_setup:err=%d, port=%u\n",
ret, (unsigned) portid);
/* init one TX queue on each port */
fflush(stdout);
ret = rte_eth_tx_queue_setup(portid, 0, nb_txd,
rte_eth_dev_socket_id(portid), &tx_conf);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_tx_queue_setup:err=%d, port=%u\n",
ret, (unsigned) portid);
/* Start device */
ret = rte_eth_dev_start(portid);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_dev_start:err=%d, port=%u\n",
ret, (unsigned) portid);
printf("done: \n");
rte_eth_promiscuous_enable(portid);
printf("Port %u, MAC address: %02X:%02X:%02X:%02X:%02X:%02X\n\n",
(unsigned) portid,
l2fwd_ports_eth_addr[portid].addr_bytes[0],
l2fwd_ports_eth_addr[portid].addr_bytes[1],
l2fwd_ports_eth_addr[portid].addr_bytes[2],
l2fwd_ports_eth_addr[portid].addr_bytes[3],
l2fwd_ports_eth_addr[portid].addr_bytes[4],
l2fwd_ports_eth_addr[portid].addr_bytes[5]);
/* initialize port stats */
memset(&port_statistics, 0, sizeof(port_statistics));
}
if (!nb_ports_available) {
rte_exit(EXIT_FAILURE,
"All available ports are disabled. Please set portmask.\n");
}
check_all_ports_link_status(nb_ports, l2fwd_enabled_port_mask);
/* 启动l2fwd线程 */
/* launch per-lcore init on every lcore */
rte_eal_mp_remote_launch(l2fwd_launch_one_lcore, NULL, CALL_MASTER);
RTE_LCORE_FOREACH_SLAVE(lcore_id) {
if (rte_eal_wait_lcore(lcore_id) < 0)
return -1;
}
return 0;
}
下面具体分析port初始化过程; 对于每一个port, 首先调用rte_eth_dev_configure配置port的收发包队列个数,并初始化收发包队列控制块;
int
rte_eth_dev_configure(uint8_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
const struct rte_eth_conf *dev_conf)
{
struct rte_eth_dev *dev;
struct rte_eth_dev_info dev_info;
int diag;
/* 仅仅能由primary进程初始化 */
/* This function is only safe when called from the primary process
* in a multi-process setup*/
PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
if (port_id >= nb_ports || port_id >= RTE_MAX_ETHPORTS) {
PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
return (-EINVAL);
}
dev = &rte_eth_devices[port_id];
/* 在PMD驱动初始化过程中,E1000的ops注冊为eth_em_ops */
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_configure, -ENOTSUP);
/* rte_eth_dev_start会把该标记为置为1 */
if (dev->data->dev_started) {
PMD_DEBUG_TRACE(
"port %d must be stopped to allow configuration\n", port_id);
return (-EBUSY);
}
/* eth_em_infos_get会返回tx,rx队列数; 本样例max_rx_queues = 1 max_tx_queues = 1 */
/*
* Check that the numbers of RX and TX queues are not greater
* than the maximum number of RX and TX queues supported by the
* configured device.
*/
(*dev->dev_ops->dev_infos_get)(dev, &dev_info);
if (nb_rx_q > dev_info.max_rx_queues) {
PMD_DEBUG_TRACE("ethdev port_id=%d nb_rx_queues=%d > %d\n",
port_id, nb_rx_q, dev_info.max_rx_queues);
return (-EINVAL);
}
if (nb_rx_q == 0) {
PMD_DEBUG_TRACE("ethdev port_id=%d nb_rx_q == 0\n", port_id);
return (-EINVAL);
}
if (nb_tx_q > dev_info.max_tx_queues) {
PMD_DEBUG_TRACE("ethdev port_id=%d nb_tx_queues=%d > %d\n",
port_id, nb_tx_q, dev_info.max_tx_queues);
return (-EINVAL);
}
if (nb_tx_q == 0) {
PMD_DEBUG_TRACE("ethdev port_id=%d nb_tx_q == 0\n", port_id);
return (-EINVAL);
}
/* dev_conf里面是tx,rx模式的配置 */
/* Copy the dev_conf parameter into the dev structure */
memcpy(&dev->data->dev_conf, dev_conf, sizeof(dev->data->dev_conf));
/* 是否收大报文 一般不须要 */
/*
* If jumbo frames are enabled, check that the maximum RX packet
* length is supported by the configured device.
*/
if (dev_conf->rxmode.jumbo_frame == 1) {
if (dev_conf->rxmode.max_rx_pkt_len >
dev_info.max_rx_pktlen) {
PMD_DEBUG_TRACE("ethdev port_id=%d max_rx_pkt_len %u"
" > max valid value %u\n",
port_id,
(unsigned)dev_conf->rxmode.max_rx_pkt_len,
(unsigned)dev_info.max_rx_pktlen);
return (-EINVAL);
}
else if (dev_conf->rxmode.max_rx_pkt_len < ETHER_MIN_LEN) {
PMD_DEBUG_TRACE("ethdev port_id=%d max_rx_pkt_len %u"
" < min valid value %u\n",
port_id,
(unsigned)dev_conf->rxmode.max_rx_pkt_len,
(unsigned)ETHER_MIN_LEN);
return (-EINVAL);
}
} else
/* Use default value */
dev->data->dev_conf.rxmode.max_rx_pkt_len = ETHER_MAX_LEN;
/* 多队列的检查, 当中各种模式DCB/RSS表示什么意思? */
/* multipe queue mode checking */
diag = rte_eth_dev_check_mq_mode(port_id, nb_rx_q, nb_tx_q, dev_conf);
if (diag != 0) {
PMD_DEBUG_TRACE("port%d rte_eth_dev_check_mq_mode = %d\n",
port_id, diag);
return diag;
}
/*
* Setup new number of RX/TX queues and reconfigure device.
*/
/* RX队列控制块内存分配 */
diag = rte_eth_dev_rx_queue_config(dev, nb_rx_q);
if (diag != 0) {
PMD_DEBUG_TRACE("port%d rte_eth_dev_rx_queue_config = %d\n",
port_id, diag);
return diag;
}
/* TX队列控制块内存分配 */
diag = rte_eth_dev_tx_queue_config(dev, nb_tx_q);
if (diag != 0) {
PMD_DEBUG_TRACE("port%d rte_eth_dev_tx_queue_config = %d\n",
port_id, diag);
rte_eth_dev_rx_queue_config(dev, 0);
return diag;
}
/* eth_em_configure, 标记intr->flags |= E1000_FLAG_NEED_LINK_UPDATE; */
diag = (*dev->dev_ops->dev_configure)(dev);
if (diag != 0) {
PMD_DEBUG_TRACE("port%d dev_configure = %d\n",
port_id, diag);
rte_eth_dev_rx_queue_config(dev, 0);
rte_eth_dev_tx_queue_config(dev, 0);
return diag;
}
return 0;
}RX queue setup
int
rte_eth_rx_queue_setup(uint8_t port_id, uint16_t rx_queue_id,
uint16_t nb_rx_desc, unsigned int socket_id,
const struct rte_eth_rxconf *rx_conf,
struct rte_mempool *mp)
{
struct rte_eth_dev *dev;
struct rte_pktmbuf_pool_private *mbp_priv;
struct rte_eth_dev_info dev_info;
/* This function is only safe when called from the primary process
* in a multi-process setup*/
PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
if (port_id >= nb_ports) {
PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
return (-EINVAL);
}
dev = &rte_eth_devices[port_id];
if (rx_queue_id >= dev->data->nb_rx_queues) {
PMD_DEBUG_TRACE("Invalid RX queue_id=%d\n", rx_queue_id);
return (-EINVAL);
}
if (dev->data->dev_started) {
PMD_DEBUG_TRACE(
"port %d must be stopped to allow configuration\n", port_id);
return -EBUSY;
}
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_setup, -ENOTSUP);
/*
* Check the size of the mbuf data buffer.
* This value must be provided in the private data of the memory pool.
* First check that the memory pool has a valid private data.
*/
(*dev->dev_ops->dev_infos_get)(dev, &dev_info);
if (mp->private_data_size < sizeof(struct rte_pktmbuf_pool_private)) {
PMD_DEBUG_TRACE("%s private_data_size %d < %d\n",
mp->name, (int) mp->private_data_size,
(int) sizeof(struct rte_pktmbuf_pool_private));
return (-ENOSPC);
}
/* mbuf data部分大小(2048) > 256 */
mbp_priv = rte_mempool_get_priv(mp);
if ((uint32_t) (mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM) <
dev_info.min_rx_bufsize) {
PMD_DEBUG_TRACE("%s mbuf_data_room_size %d < %d "
"(RTE_PKTMBUF_HEADROOM=%d + min_rx_bufsize(dev)"
"=%d)\n",
mp->name,
(int)mbp_priv->mbuf_data_room_size,
(int)(RTE_PKTMBUF_HEADROOM +
dev_info.min_rx_bufsize),
(int)RTE_PKTMBUF_HEADROOM,
(int)dev_info.min_rx_bufsize);
return (-EINVAL);
}
/* eth_em_rx_queue_setup, 初始化收包描写叙述符 */
return (*dev->dev_ops->rx_queue_setup)(dev, rx_queue_id, nb_rx_desc,
socket_id, rx_conf, mp);
}
int
rte_eth_rx_queue_setup(uint8_t port_id, uint16_t rx_queue_id,
uint16_t nb_rx_desc, unsigned int socket_id,
const struct rte_eth_rxconf *rx_conf,
struct rte_mempool *mp)
{
struct rte_eth_dev *dev;
struct rte_pktmbuf_pool_private *mbp_priv;
struct rte_eth_dev_info dev_info;
/* This function is only safe when called from the primary process
* in a multi-process setup*/
PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
if (port_id >= nb_ports) {
PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
return (-EINVAL);
}
dev = &rte_eth_devices[port_id];
if (rx_queue_id >= dev->data->nb_rx_queues) {
PMD_DEBUG_TRACE("Invalid RX queue_id=%d\n", rx_queue_id);
return (-EINVAL);
}
if (dev->data->dev_started) {
PMD_DEBUG_TRACE(
"port %d must be stopped to allow configuration\n", port_id);
return -EBUSY;
}
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_queue_setup, -ENOTSUP);
/*
* Check the size of the mbuf data buffer.
* This value must be provided in the private data of the memory pool.
* First check that the memory pool has a valid private data.
*/
(*dev->dev_ops->dev_infos_get)(dev, &dev_info);
if (mp->private_data_size < sizeof(struct rte_pktmbuf_pool_private)) {
PMD_DEBUG_TRACE("%s private_data_size %d < %d\n",
mp->name, (int) mp->private_data_size,
(int) sizeof(struct rte_pktmbuf_pool_private));
return (-ENOSPC);
}
/* mbuf data部分大小(2048) > 256 */
mbp_priv = rte_mempool_get_priv(mp);
if ((uint32_t) (mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM) <
dev_info.min_rx_bufsize) {
PMD_DEBUG_TRACE("%s mbuf_data_room_size %d < %d "
"(RTE_PKTMBUF_HEADROOM=%d + min_rx_bufsize(dev)"
"=%d)\n",
mp->name,
(int)mbp_priv->mbuf_data_room_size,
(int)(RTE_PKTMBUF_HEADROOM +
dev_info.min_rx_bufsize),
(int)RTE_PKTMBUF_HEADROOM,
(int)dev_info.min_rx_bufsize);
return (-EINVAL);
}
/* eth_em_rx_queue_setup, 初始化收包描写叙述符 */
return (*dev->dev_ops->rx_queue_setup)(dev, rx_queue_id, nb_rx_desc,
socket_id, rx_conf, mp);
}TX
queue setup
int
rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
uint16_t nb_tx_desc, unsigned int socket_id,
const struct rte_eth_txconf *tx_conf)
{
struct rte_eth_dev *dev;
/* This function is only safe when called from the primary process
* in a multi-process setup*/
PROC_PRIMARY_OR_ERR_RET(-E_RTE_SECONDARY);
if (port_id >= RTE_MAX_ETHPORTS || port_id >= nb_ports) {
PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
return (-EINVAL);
}
dev = &rte_eth_devices[port_id];
if (tx_queue_id >= dev->data->nb_tx_queues) {
PMD_DEBUG_TRACE("Invalid TX queue_id=%d\n", tx_queue_id);
return (-EINVAL);
}
/* 必须在设备启动前做初始化操作 */
if (dev->data->dev_started) {
PMD_DEBUG_TRACE(
"port %d must be stopped to allow configuration\n", port_id);
return -EBUSY;
}
/* 调用PMD驱动的tx_queue_setup */
FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_queue_setup, -ENOTSUP);
return (*dev->dev_ops->tx_queue_setup)(dev, tx_queue_id, nb_tx_desc,
socket_id, tx_conf);
}int
eth_em_tx_queue_setup(struct rte_eth_dev *dev,
uint16_t queue_idx,
uint16_t nb_desc,
unsigned int socket_id,
const struct rte_eth_txconf *tx_conf)
{
const struct rte_memzone *tz;
struct em_tx_queue *txq;
struct e1000_hw *hw;
uint32_t tsize;
uint16_t tx_rs_thresh, tx_free_thresh;
hw = E1000_DEV_PRIVATE_TO_HW(dev->data->dev_private);
/* tx descriptor必须是cache line对齐的 */
/*
* Validate number of transmit descriptors.
* It must not exceed hardware maximum, and must be multiple
* of EM_ALIGN.
*/
if (((nb_desc * sizeof(*txq->tx_ring)) % EM_ALIGN) != 0 ||
(nb_desc > EM_MAX_RING_DESC) ||
(nb_desc < EM_MIN_RING_DESC)) {
return -(EINVAL);
}
/* threshold 配置 */
tx_free_thresh = tx_conf->tx_free_thresh;
if (tx_free_thresh == 0)
tx_free_thresh = (uint16_t)RTE_MIN(nb_desc / 4,
DEFAULT_TX_FREE_THRESH);
tx_rs_thresh = tx_conf->tx_rs_thresh;
if (tx_rs_thresh == 0)
tx_rs_thresh = (uint16_t)RTE_MIN(tx_free_thresh,
DEFAULT_TX_RS_THRESH);
if (tx_free_thresh >= (nb_desc - 3)) {
RTE_LOG(ERR, PMD, "tx_free_thresh must be less than the "
"number of TX descriptors minus 3. (tx_free_thresh=%u "
"port=%d queue=%d)\n", (unsigned int)tx_free_thresh,
(int)dev->data->port_id, (int)queue_idx);
return -(EINVAL);
}
if (tx_rs_thresh > tx_free_thresh) {
RTE_LOG(ERR, PMD, "tx_rs_thresh must be less than or equal to "
"tx_free_thresh. (tx_free_thresh=%u tx_rs_thresh=%u "
"port=%d queue=%d)\n", (unsigned int)tx_free_thresh,
(unsigned int)tx_rs_thresh, (int)dev->data->port_id,
(int)queue_idx);
return -(EINVAL);
}
/*
* If rs_bit_thresh is greater than 1, then TX WTHRESH should be
* set to 0. If WTHRESH is greater than zero, the RS bit is ignored
* by the NIC and all descriptors are written back after the NIC
* accumulates WTHRESH descriptors.
*/
if (tx_conf->tx_thresh.wthresh != 0 && tx_rs_thresh != 1) {
RTE_LOG(ERR, PMD, "TX WTHRESH must be set to 0 if "
"tx_rs_thresh is greater than 1. (tx_rs_thresh=%u "
"port=%d queue=%d)\n", (unsigned int)tx_rs_thresh,
(int)dev->data->port_id, (int)queue_idx);
return -(EINVAL);
}
/* txq不为空,释放原先的队列中的mbuf和txq */
/* Free memory prior to re-allocation if needed... */
if (dev->data->tx_queues[queue_idx] != NULL) {
em_tx_queue_release(dev->data->tx_queues[queue_idx]);
dev->data->tx_queues[queue_idx] = NULL;
}
/* 分配名为rte_em_pmd_tx_ring_p_q的memzone, 用于存放EM_MAX_RING_DESC个tx descriptor */
/*
* Allocate TX ring hardware descriptors. A memzone large enough to
* handle the maximum ring size is allocated in order to allow for
* resizing in later calls to the queue setup function.
*/
tsize = sizeof (txq->tx_ring[0]) * EM_MAX_RING_DESC;
if ((tz = ring_dma_zone_reserve(dev, "tx_ring", queue_idx, tsize,
socket_id)) == NULL)
return (-ENOMEM);
/* txq内存分配 */
/* Allocate the tx queue data structure. */
if ((txq = rte_zmalloc("ethdev TX queue", sizeof(*txq),
CACHE_LINE_SIZE)) == NULL)
return (-ENOMEM);
/* txq sw_ring内存分配 */
/* Allocate software ring */
if ((txq->sw_ring = rte_zmalloc("txq->sw_ring",
sizeof(txq->sw_ring[0]) * nb_desc,
CACHE_LINE_SIZE)) == NULL) {
em_tx_queue_release(txq);
return (-ENOMEM);
}
txq->nb_tx_desc = nb_desc;
txq->tx_free_thresh = tx_free_thresh;
txq->tx_rs_thresh = tx_rs_thresh;
txq->pthresh = tx_conf->tx_thresh.pthresh;
txq->hthresh = tx_conf->tx_thresh.hthresh;
txq->wthresh = tx_conf->tx_thresh.wthresh;
txq->queue_id = queue_idx;
txq->port_id = dev->data->port_id;
txq->tdt_reg_addr = E1000_PCI_REG_ADDR(hw, E1000_TDT(queue_idx));
/* tx_ring的物理地址 */
#ifndef RTE_LIBRTE_XEN_DOM0
txq->tx_ring_phys_addr = (uint64_t) tz->phys_addr;
#else
txq->tx_ring_phys_addr = rte_mem_phy2mch(tz->memseg_id, tz->phys_addr);
#endif
/* tx_ring的虚拟地址 */
txq->tx_ring = (struct e1000_data_desc *) tz->addr;
PMD_INIT_LOG(DEBUG, "sw_ring=%p hw_ring=%p dma_addr=0x%"PRIx64"\n",
txq->sw_ring, txq->tx_ring, txq->tx_ring_phys_addr);
/* 环状队列初始化,每一个entry的next指向下一个,最后一个指向第一个 */
em_reset_tx_queue(txq);
dev->data->tx_queues[queue_idx] = txq;
return (0);
}port初始化的最后一步是使能port收发包功能,当中主要是通知E1000驱动tx
ring和rx ring的地址, 细节就不再跟进
void
eth_em_tx_init(struct rte_eth_dev *dev)
{
struct e1000_hw *hw;
struct em_tx_queue *txq;
uint32_t tctl;
uint32_t txdctl;
uint16_t i;
hw = E1000_DEV_PRIVATE_TO_HW(dev->data->dev_private);
/* 把每个queue的tx ring的物理地址通告给E1000驱动 */
/* Setup the Base and Length of the Tx Descriptor Rings. */
for (i = 0; i < dev->data->nb_tx_queues; i++) {
uint64_t bus_addr;
txq = dev->data->tx_queues[i];
bus_addr = txq->tx_ring_phys_addr;
E1000_WRITE_REG(hw, E1000_TDLEN(i),
txq->nb_tx_desc *
sizeof(*txq->tx_ring));
E1000_WRITE_REG(hw, E1000_TDBAH(i),
(uint32_t)(bus_addr >> 32));
E1000_WRITE_REG(hw, E1000_TDBAL(i), (uint32_t)bus_addr);
/* Setup the HW Tx Head and Tail descriptor pointers. */
E1000_WRITE_REG(hw, E1000_TDT(i), 0);
E1000_WRITE_REG(hw, E1000_TDH(i), 0);
/* Setup Transmit threshold registers. */
txdctl = E1000_READ_REG(hw, E1000_TXDCTL(i));
/*
* bit 22 is reserved, on some models should always be 0,
* on others - always 1.
*/
txdctl &= E1000_TXDCTL_COUNT_DESC;
txdctl |= txq->pthresh & 0x3F;
txdctl |= (txq->hthresh & 0x3F) << 8;
txdctl |= (txq->wthresh & 0x3F) << 16;
txdctl |= E1000_TXDCTL_GRAN;
E1000_WRITE_REG(hw, E1000_TXDCTL(i), txdctl);
}
/* Program the Transmit Control Register. */
tctl = E1000_READ_REG(hw, E1000_TCTL);
tctl &= ~E1000_TCTL_CT;
tctl |= (E1000_TCTL_PSP | E1000_TCTL_RTLC | E1000_TCTL_EN |
(E1000_COLLISION_THRESHOLD << E1000_CT_SHIFT));
/* This write will effectively turn on the transmit unit. */
E1000_WRITE_REG(hw, E1000_TCTL, tctl);
}int
eth_em_rx_init(struct rte_eth_dev *dev)
{
struct e1000_hw *hw;
struct em_rx_queue *rxq;
uint32_t rctl;
uint32_t rfctl;
uint32_t rxcsum;
uint32_t rctl_bsize;
uint16_t i;
int ret;
hw = E1000_DEV_PRIVATE_TO_HW(dev->data->dev_private);
/*
* Make sure receives are disabled while setting
* up the descriptor ring.
*/
rctl = E1000_READ_REG(hw, E1000_RCTL);
E1000_WRITE_REG(hw, E1000_RCTL, rctl & ~E1000_RCTL_EN);
rfctl = E1000_READ_REG(hw, E1000_RFCTL);
/* Disable extended descriptor type. */
rfctl &= ~E1000_RFCTL_EXTEN;
/* Disable accelerated acknowledge */
if (hw->mac.type == e1000_82574)
rfctl |= E1000_RFCTL_ACK_DIS;
E1000_WRITE_REG(hw, E1000_RFCTL, rfctl);
/*
* XXX TEMPORARY WORKAROUND: on some systems with 82573
* long latencies are observed, like Lenovo X60. This
* change eliminates the problem, but since having positive
* values in RDTR is a known source of problems on other
* platforms another solution is being sought.
*/
if (hw->mac.type == e1000_82573)
E1000_WRITE_REG(hw, E1000_RDTR, 0x20);
dev->rx_pkt_burst = (eth_rx_burst_t)eth_em_recv_pkts;
/* 计算pkt buf的大小 */
/* Determine RX bufsize. */
rctl_bsize = EM_MAX_BUF_SIZE;
for (i = 0; i < dev->data->nb_rx_queues; i++) {
struct rte_pktmbuf_pool_private *mbp_priv;
uint32_t buf_size;
rxq = dev->data->rx_queues[i];
mbp_priv = rte_mempool_get_priv(rxq->mb_pool);
buf_size = mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM;
rctl_bsize = RTE_MIN(rctl_bsize, buf_size);
}
rctl |= em_rctl_bsize(hw->mac.type, &rctl_bsize);
/* Configure and enable each RX queue. */
for (i = 0; i < dev->data->nb_rx_queues; i++) {
uint64_t bus_addr;
uint32_t rxdctl;
rxq = dev->data->rx_queues[i];
/* 从mbuf pool中分配mbuf, 填写到rxq->sw_ring,记录每一个pkt buf的物理地址到rxq->rx_ring */
/* Allocate buffers for descriptor rings and setup queue */
ret = em_alloc_rx_queue_mbufs(rxq);
if (ret)
return ret;
/* 把rx ring的物理地址通告给E1000驱动 */
/*
* Reset crc_len in case it was changed after queue setup by a
* call to configure
*/
rxq->crc_len =
(uint8_t)(dev->data->dev_conf.rxmode.hw_strip_crc ?
: ETHER_CRC_LEN);
bus_addr = rxq->rx_ring_phys_addr;
E1000_WRITE_REG(hw, E1000_RDLEN(i),
rxq->nb_rx_desc *
sizeof(*rxq->rx_ring));
E1000_WRITE_REG(hw, E1000_RDBAH(i),
(uint32_t)(bus_addr >> 32));
E1000_WRITE_REG(hw, E1000_RDBAL(i), (uint32_t)bus_addr);
E1000_WRITE_REG(hw, E1000_RDH(i), 0);
E1000_WRITE_REG(hw, E1000_RDT(i), rxq->nb_rx_desc - 1);
rxdctl = E1000_READ_REG(hw, E1000_RXDCTL(0));
rxdctl &= 0xFE000000;
rxdctl |= rxq->pthresh & 0x3F;
rxdctl |= (rxq->hthresh & 0x3F) << 8;
rxdctl |= (rxq->wthresh & 0x3F) << 16;
rxdctl |= E1000_RXDCTL_GRAN;
E1000_WRITE_REG(hw, E1000_RXDCTL(i), rxdctl);
/* 收大报文用的收包函数 */
/*
* Due to EM devices not having any sort of hardware
* limit for packet length, jumbo frame of any size
* can be accepted, thus we have to enable scattered
* rx if jumbo frames are enabled (or if buffer size
* is too small to accomodate non-jumbo packets)
* to avoid splitting packets that don‘t fit into
* one buffer.
*/
if (dev->data->dev_conf.rxmode.jumbo_frame ||
rctl_bsize < ETHER_MAX_LEN) {
dev->rx_pkt_burst =
(eth_rx_burst_t)eth_em_recv_scattered_pkts;
dev->data->scattered_rx = 1;
}
}
/* 下面省略 */
...
return 0;
}
到此port初始化完毕,比启动,回到main函数中, 在每一个lcore上启动循环收包函数
/* launch per-lcore init on every lcore */ rte_eal_mp_remote_launch(l2fwd_launch_one_lcore, NULL, CALL_MASTER);
lcore的主线程处理例如以下
/* main processing loop */
static void
l2fwd_main_loop(void)
{
struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
struct rte_mbuf *m;
unsigned lcore_id;
uint64_t prev_tsc, diff_tsc, cur_tsc, timer_tsc;
unsigned i, j, portid, nb_rx;
struct lcore_queue_conf *qconf;
const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1) / US_PER_S * BURST_TX_DRAIN_US;
prev_tsc = 0;
timer_tsc = 0;
lcore_id = rte_lcore_id();
qconf = &lcore_queue_conf[lcore_id];
if (qconf->n_rx_port == 0) {
RTE_LOG(INFO, L2FWD, "lcore %u has nothing to do\n", lcore_id);
return;
}
RTE_LOG(INFO, L2FWD, "entering main loop on lcore %u\n", lcore_id);
/* 当前lcore须要处理哪些port(queue) */
for (i = 0; i < qconf->n_rx_port; i++) {
portid = qconf->rx_port_list[i];
RTE_LOG(INFO, L2FWD, " -- lcoreid=%u portid=%u\n", lcore_id,
portid);
}
while (1) {
cur_tsc = rte_rdtsc();
/*
* TX burst queue drain
*/
diff_tsc = cur_tsc - prev_tsc;
/* 隔一段时间才把全部要发送的报文发送出去并打印统计信息 */
if (unlikely(diff_tsc > drain_tsc)) {
for (portid = 0; portid < RTE_MAX_ETHPORTS; portid++) {
/* 当前port没有须要发送的报文 */
if (qconf->tx_mbufs[portid].len == 0)
continue;
/* 调用device的发包函数并统计发送的报文个数 */
l2fwd_send_burst(&lcore_queue_conf[lcore_id],
qconf->tx_mbufs[portid].len,
(uint8_t) portid);
/* 到此应该当前端口须要发送的报文全部发送,因此len置为0 */
qconf->tx_mbufs[portid].len = 0;
}
/* if timer is enabled */
if (timer_period > 0) {
/* advance the timer */
timer_tsc += diff_tsc;
/* if timer has reached its timeout */
if (unlikely(timer_tsc >= (uint64_t) timer_period)) {
/* do this only on master core */
if (lcore_id == rte_get_master_lcore()) {
print_stats();
/* reset the timer */
timer_tsc = 0;
}
}
}
prev_tsc = cur_tsc;
}
/* 当前lcore须要处理的queue */
/*
* Read packet from RX queues
*/
for (i = 0; i < qconf->n_rx_port; i++) {
portid = qconf->rx_port_list[i];
/* 当前port仅仅有queue0 */
nb_rx = rte_eth_rx_burst((uint8_t) portid, 0,
pkts_burst, MAX_PKT_BURST);
/* 更新收包统计 */
port_statistics[portid].rx += nb_rx;
/* 把全部收上来的报文改动目的MAC后增加到发包队列 */
for (j = 0; j < nb_rx; j++) {
m = pkts_burst[j];
/* PKT DATA部分加载cache,这个好像收包部分已经prefetch过了 */
rte_prefetch0(rte_pktmbuf_mtod(m, void *));
/* forword */
l2fwd_simple_forward(m, portid);
}
}
}
}首先看报文是怎样收上来的,
调用device的rx_pkt_burst
static inline uint16_t
rte_eth_rx_burst(uint8_t port_id, uint16_t queue_id,
struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
{
struct rte_eth_dev *dev;
dev = &rte_eth_devices[port_id];
return (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id], rx_pkts, nb_pkts);
}PMD的收包函数例如以下:
uint16_t
eth_em_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
uint16_t nb_pkts)
{
/* volatile防止编译器优化,每次使用必须又一次从memory中取而不是用寄存器的值 */
volatile struct e1000_rx_desc *rx_ring;
volatile struct e1000_rx_desc *rxdp;
struct em_rx_queue *rxq;
struct em_rx_entry *sw_ring;
struct em_rx_entry *rxe;
struct rte_mbuf *rxm;
struct rte_mbuf *nmb;
struct e1000_rx_desc rxd;
uint64_t dma_addr;
uint16_t pkt_len;
uint16_t rx_id;
uint16_t nb_rx;
uint16_t nb_hold;
uint8_t status;
rxq = rx_queue;
nb_rx = 0;
nb_hold = 0;
rx_id = rxq->rx_tail; /* 当前收包位置 */
rx_ring = rxq->rx_ring; /* rx descriptor */
sw_ring = rxq->sw_ring; /* mbuf */
/* 一次性收32个报文 */
while (nb_rx < nb_pkts) {
/*
* The order of operations here is important as the DD status
* bit must not be read after any other descriptor fields.
* rx_ring and rxdp are pointing to volatile data so the order
* of accesses cannot be reordered by the compiler. If they were
* not volatile, they could be reordered which could lead to
* using invalid descriptor fields when read from rxd.
*/
/* 当前报文的descriptor */
rxdp = &rx_ring[rx_id];
/* 结束标记,必须首先读取 */
status = rxdp->status;
if (! (status & E1000_RXD_STAT_DD))
break;
/* 复制一份 */
rxd = *rxdp;
/*
* End of packet.
*
* If the E1000_RXD_STAT_EOP flag is not set, the RX packet is
* likely to be invalid and to be dropped by the various
* validation checks performed by the network stack.
*
* Allocate a new mbuf to replenish the RX ring descriptor.
* If the allocation fails:
* - arrange for that RX descriptor to be the first one
* being parsed the next time the receive function is
* invoked [on the same queue].
*
* - Stop parsing the RX ring and return immediately.
*
* This policy do not drop the packet received in the RX
* descriptor for which the allocation of a new mbuf failed.
* Thus, it allows that packet to be later retrieved if
* mbuf have been freed in the mean time.
* As a side effect, holding RX descriptors instead of
* systematically giving them back to the NIC may lead to
* RX ring exhaustion situations.
* However, the NIC can gracefully prevent such situations
* to happen by sending specific "back-pressure" flow control
* frames to its peer(s).
*/
PMD_RX_LOG(DEBUG, "\nport_id=%u queue_id=%u rx_id=%u "
"status=0x%x pkt_len=%u\n",
(unsigned) rxq->port_id, (unsigned) rxq->queue_id,
(unsigned) rx_id, (unsigned) status,
(unsigned) rte_le_to_cpu_16(rxd.length));
/* 分配新的mbuf给驱动 */
nmb = rte_rxmbuf_alloc(rxq->mb_pool);
if (nmb == NULL) {
PMD_RX_LOG(DEBUG, "RX mbuf alloc failed port_id=%u "
"queue_id=%u\n",
(unsigned) rxq->port_id,
(unsigned) rxq->queue_id);
rte_eth_devices[rxq->port_id].data->rx_mbuf_alloc_failed++;
break;
}
/* 表示当前descriptor被上层软件占用 */
nb_hold++;
/* 当前收到的mbuf */
rxe = &sw_ring[rx_id];
/* 收包位置,假设超过环状数组则回滚 */
rx_id++;
if (rx_id == rxq->nb_rx_desc)
rx_id = 0;
/* mbuf加载cache下次循环使用 */
/* Prefetch next mbuf while processing current one. */
rte_em_prefetch(sw_ring[rx_id].mbuf);
/* 取下一个descriptor,以及mbuf指针下次循环使用 */
/* 一个cache line是4个descriptor大小(64字节) */
/*
* When next RX descriptor is on a cache-line boundary,
* prefetch the next 4 RX descriptors and the next 8 pointers
* to mbufs.
*/
if ((rx_id & 0x3) == 0) {
rte_em_prefetch(&rx_ring[rx_id]);
rte_em_prefetch(&sw_ring[rx_id]);
}
/* Rearm RXD: attach new mbuf and reset status to zero. */
/* 替换sw_ring entry的mbuf指针 */
rxm = rxe->mbuf;
rxe->mbuf = nmb;
dma_addr =
rte_cpu_to_le_64(RTE_MBUF_DATA_DMA_ADDR_DEFAULT(nmb));
rxdp->buffer_addr = dma_addr;
/* 重置当前descriptor的status */
rxdp->status = 0;
/*
* Initialize the returned mbuf.
* 1) setup generic mbuf fields:
* - number of segments,
* - next segment,
* - packet length,
* - RX port identifier.
* 2) integrate hardware offload data, if any:
* - RSS flag & hash,
* - IP checksum flag,
* - VLAN TCI, if any,
* - error flags.
*/
pkt_len = (uint16_t) (rte_le_to_cpu_16(rxd.length) -
rxq->crc_len);
rxm->pkt.data = (char*) rxm->buf_addr + RTE_PKTMBUF_HEADROOM;
rte_packet_prefetch(rxm->pkt.data);
rxm->pkt.nb_segs = 1;
rxm->pkt.next = NULL;
rxm->pkt.pkt_len = pkt_len;
rxm->pkt.data_len = pkt_len;
rxm->pkt.in_port = rxq->port_id;
rxm->ol_flags = rx_desc_status_to_pkt_flags(status);
rxm->ol_flags = (uint16_t)(rxm->ol_flags |
rx_desc_error_to_pkt_flags(rxd.errors));
/* Only valid if PKT_RX_VLAN_PKT set in pkt_flags */
rxm->pkt.vlan_macip.f.vlan_tci = rte_le_to_cpu_16(rxd.special);
/* 把收到的mbuf返回给用户 */
/*
* Store the mbuf address into the next entry of the array
* of returned packets.
*/
rx_pkts[nb_rx++] = rxm;
}
/* 收包位置更新 */
rxq->rx_tail = rx_id;
/* 更新被上层软件使用的descriptor个数 */
/*
* If the number of free RX descriptors is greater than the RX free
* threshold of the queue, advance the Receive Descriptor Tail (RDT)
* register.
* Update the RDT with the value of the last processed RX descriptor
* minus 1, to guarantee that the RDT register is never equal to the
* RDH register, which creates a "full" ring situtation from the
* hardware point of view...
*/
nb_hold = (uint16_t) (nb_hold + rxq->nb_rx_hold);
if (nb_hold > rxq->rx_free_thresh) {
PMD_RX_LOG(DEBUG, "port_id=%u queue_id=%u rx_tail=%u "
"nb_hold=%u nb_rx=%u\n",
(unsigned) rxq->port_id, (unsigned) rxq->queue_id,
(unsigned) rx_id, (unsigned) nb_hold,
(unsigned) nb_rx);
rx_id = (uint16_t) ((rx_id == 0) ?
(rxq->nb_rx_desc - 1) : (rx_id - 1));
E1000_PCI_REG_WRITE(rxq->rdt_reg_addr, rx_id);
nb_hold = 0;
}
rxq->nb_rx_hold = nb_hold;
return (nb_rx);
}
发包函数
static inline uint16_t
rte_eth_tx_burst(uint8_t port_id, uint16_t queue_id,
struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
{
struct rte_eth_dev *dev;
dev = &rte_eth_devices[port_id];
return (*dev->tx_pkt_burst)(dev->data->tx_queues[queue_id], tx_pkts, nb_pkts);
}调用的PMD的发包函数
uint16_t
eth_em_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
uint16_t nb_pkts)
{
struct em_tx_queue *txq;
struct em_tx_entry *sw_ring;
struct em_tx_entry *txe, *txn;
volatile struct e1000_data_desc *txr;
volatile struct e1000_data_desc *txd;
struct rte_mbuf *tx_pkt;
struct rte_mbuf *m_seg;
uint64_t buf_dma_addr;
uint32_t popts_spec;
uint32_t cmd_type_len;
uint16_t slen;
uint16_t ol_flags;
uint16_t tx_id;
uint16_t tx_last;
uint16_t nb_tx;
uint16_t nb_used;
uint16_t tx_ol_req;
uint32_t ctx;
uint32_t new_ctx;
union rte_vlan_macip hdrlen;
txq = tx_queue;
sw_ring = txq->sw_ring;
txr = txq->tx_ring;
/* 发包位置 */
tx_id = txq->tx_tail;
/* 先把旧的已发送的mbuf回收,然后把新的要发送的mbuf写入 */
txe = &sw_ring[tx_id];
/* 可用tx descriptor太少的话做cleanup */
/* Determine if the descriptor ring needs to be cleaned. */
if ((txq->nb_tx_desc - txq->nb_tx_free) > txq->tx_free_thresh) {
em_xmit_cleanup(txq);
}
/* nb_pkts为一共要发送的报文个数(32) */
/* TX loop */
for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
new_ctx = 0;
/* 要发送的mbuf指针 */
tx_pkt = *tx_pkts++;
/* 加载L1,L2 cache,用于释放mbuf */
RTE_MBUF_PREFETCH_TO_FREE(txe->mbuf);
/*
* Determine how many (if any) context descriptors
* are needed for offload functionality.
*/
ol_flags = tx_pkt->ol_flags;
/* If hardware offload required */
tx_ol_req = (uint16_t)(ol_flags & (PKT_TX_IP_CKSUM |
PKT_TX_L4_MASK));
if (tx_ol_req) {
hdrlen = tx_pkt->pkt.vlan_macip;
/* 检查是否须要新的context descriptor */
/* If new context to be built or reuse the exist ctx. */
ctx = what_ctx_update(txq, tx_ol_req, hdrlen);
/* Only allocate context descriptor if required*/
new_ctx = (ctx == EM_CTX_NUM);
}
/* 须要的descriptor个数为报文的segment数+是否须要context descriptor */
/*
* Keep track of how many descriptors are used this loop
* This will always be the number of segments + the number of
* Context descriptors required to transmit the packet
*/
nb_used = (uint16_t)(tx_pkt->pkt.nb_segs + new_ctx);
/* 结束位置, 从tx_id处用起,因此-1 */
/*
* The number of descriptors that must be allocated for a
* packet is the number of segments of that packet, plus 1
* Context Descriptor for the hardware offload, if any.
* Determine the last TX descriptor to allocate in the TX ring
* for the packet, starting from the current position (tx_id)
* in the ring.
*/
tx_last = (uint16_t) (tx_id + nb_used - 1);
/* 回滚 */
/* Circular ring */
if (tx_last >= txq->nb_tx_desc)
tx_last = (uint16_t) (tx_last - txq->nb_tx_desc);
PMD_TX_LOG(DEBUG, "port_id=%u queue_id=%u pktlen=%u"
" tx_first=%u tx_last=%u\n",
(unsigned) txq->port_id,
(unsigned) txq->queue_id,
(unsigned) tx_pkt->pkt.pkt_len,
(unsigned) tx_id,
(unsigned) tx_last);
/*
* Make sure there are enough TX descriptors available to
* transmit the entire packet.
* nb_used better be less than or equal to txq->tx_rs_thresh
*/
while (unlikely (nb_used > txq->nb_tx_free)) {
PMD_TX_FREE_LOG(DEBUG,
"Not enough free TX descriptors "
"nb_used=%4u nb_free=%4u "
"(port=%d queue=%d)",
nb_used, txq->nb_tx_free,
txq->port_id, txq->queue_id);
if (em_xmit_cleanup(txq) != 0) {
/* Could not clean any descriptors */
if (nb_tx == 0)
return (0);
goto end_of_tx;
}
}
/*
* By now there are enough free TX descriptors to transmit
* the packet.
*/
/*
* Set common flags of all TX Data Descriptors.
*
* The following bits must be set in all Data Descriptors:
* - E1000_TXD_DTYP_DATA
* - E1000_TXD_DTYP_DEXT
*
* The following bits must be set in the first Data Descriptor
* and are ignored in the other ones:
* - E1000_TXD_POPTS_IXSM
* - E1000_TXD_POPTS_TXSM
*
* The following bits must be set in the last Data Descriptor
* and are ignored in the other ones:
* - E1000_TXD_CMD_VLE
* - E1000_TXD_CMD_IFCS
*
* The following bits must only be set in the last Data
* Descriptor:
* - E1000_TXD_CMD_EOP
*
* The following bits can be set in any Data Descriptor, but
* are only set in the last Data Descriptor:
* - E1000_TXD_CMD_RS
*/
cmd_type_len = E1000_TXD_CMD_DEXT | E1000_TXD_DTYP_D |
E1000_TXD_CMD_IFCS;
popts_spec = 0;
/* Set VLAN Tag offload fields. */
if (ol_flags & PKT_TX_VLAN_PKT) {
cmd_type_len |= E1000_TXD_CMD_VLE;
popts_spec = tx_pkt->pkt.vlan_macip.f.vlan_tci <<
E1000_TXD_VLAN_SHIFT;
}
if (tx_ol_req) {
/*
* Setup the TX Context Descriptor if required
*/
if (new_ctx) {
volatile struct e1000_context_desc *ctx_txd;
/* 假设须要context descriptor, tx_id处存放ctx的tx descriptor */
ctx_txd = (volatile struct e1000_context_desc *)
&txr[tx_id];
/* 下一个tx descriptor */
txn = &sw_ring[txe->next_id];
RTE_MBUF_PREFETCH_TO_FREE(txn->mbuf);
if (txe->mbuf != NULL) {
rte_pktmbuf_free_seg(txe->mbuf);
txe->mbuf = NULL;
}
/* 设置ctx值到txq */
em_set_xmit_ctx(txq, ctx_txd, tx_ol_req,
hdrlen);
txe->last_id = tx_last;
/* tx_id,txe 都分别指向下一个 */
tx_id = txe->next_id;
txe = txn;
}
/*
* Setup the TX Data Descriptor,
* This path will go through
* whatever new/reuse the context descriptor
*/
popts_spec |= tx_desc_cksum_flags_to_upper(ol_flags);
}
m_seg = tx_pkt;
do {
txd = &txr[tx_id];
txn = &sw_ring[txe->next_id];
/* 已发送的mbuf,回收,实际的pkt addr已经写入tx descriptor了,mbuf已经没用了 */
if (txe->mbuf != NULL)
rte_pktmbuf_free_seg(txe->mbuf);
/* 当前mbuf增加txe */
txe->mbuf = m_seg;
/*
* Set up Transmit Data Descriptor.
*/
slen = m_seg->pkt.data_len;
buf_dma_addr = RTE_MBUF_DATA_DMA_ADDR(m_seg);
txd->buffer_addr = rte_cpu_to_le_64(buf_dma_addr);
txd->lower.data = rte_cpu_to_le_32(cmd_type_len | slen);
txd->upper.data = rte_cpu_to_le_32(popts_spec);
txe->last_id = tx_last;
/* tx_id更新 */
tx_id = txe->next_id;
txe = txn;
m_seg = m_seg->pkt.next;
} while (m_seg != NULL);
/* 驱动相关的flag,vlan ip checksum之类,略过 */
/*
* The last packet data descriptor needs End Of Packet (EOP)
*/
cmd_type_len |= E1000_TXD_CMD_EOP;
txq->nb_tx_used = (uint16_t)(txq->nb_tx_used + nb_used);
txq->nb_tx_free = (uint16_t)(txq->nb_tx_free - nb_used);
/* Set RS bit only on threshold packets‘ last descriptor */
if (txq->nb_tx_used >= txq->tx_rs_thresh) {
PMD_TX_FREE_LOG(DEBUG,
"Setting RS bit on TXD id="
"%4u (port=%d queue=%d)",
tx_last, txq->port_id, txq->queue_id);
cmd_type_len |= E1000_TXD_CMD_RS;
/* Update txq RS bit counters */
txq->nb_tx_used = 0;
}
txd->lower.data |= rte_cpu_to_le_32(cmd_type_len);
}
end_of_tx:
rte_wmb();
/* 通知驱动有报文发送 */
/*
* Set the Transmit Descriptor Tail (TDT)
*/
PMD_TX_LOG(DEBUG, "port_id=%u queue_id=%u tx_tail=%u nb_tx=%u",
(unsigned) txq->port_id, (unsigned) txq->queue_id,
(unsigned) tx_id, (unsigned) nb_tx);
E1000_PCI_REG_WRITE(txq->tdt_reg_addr, tx_id);
/* 更新tx队列位置 */
txq->tx_tail = tx_id;
return (nb_tx);
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