dpdk设置mtu-DPDK中文网

DPDK本身不直接设置MTU，但是可以通过在初始化时绑定物理网卡并设置其MTU值来间接地实现。

以下是一个示例的DPDK应用程序代码，在初始化时绑定一个物理网卡作为DPDK端口，并设置其MTU值：

#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>
#include <errno.h>

#include <rte_eal.h>
#include <rte_ethdev.h>

#define PORT_NUM    0       /* DPDK port number */
#define MTU_SIZE    9000    /* MTU size to be set */

int main(int argc, char** argv)
{
    int ret;
    uint16_t nb_ports;

    /* Initialize the Environment Abstraction Layer (EAL) */
    ret = rte_eal_init(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error: Cannot init EAL\n");

    /* Get the number of available ports */
    nb_ports = rte_eth_dev_count_avail();
    if (nb_ports == 0)
        rte_exit(EXIT_FAILURE, "Error: No Ethernet ports found\n");

    /* Configure port and set its MTU */
    struct rte_eth_conf port_conf = {
        .rxmode = { .max_rx_pkt_len = MTU_SIZE },
        .txmode = { .mq_mode = ETH_MQ_TX_NONE },
     };
     struct rte_eth_txconf txq_conf;
     memset(&txq_conf, 0, sizeof(struct rte_eth_txconf));
     ret = rte_eth_dev_configure(PORT_NUM, 1, 1, &port_conf);
     if (ret != 0)
         rte_exit(EXIT_FAILURE, "Error: Cannot configure port %u (%d)\n", PORT_NUM, ret);
     ret = rte_eth_dev_adjust_mtu(PORT_NUM, MTU_SIZE);
     if (ret != 0)
         rte_exit(EXIT_FAILURE, "Error: Cannot set MTU of port %u (%d)\n", PORT_NUM, ret);

    /* Start the Ethernet port */
    ret = rte_eth_dev_start(PORT_NUM);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error: Cannot start port %u (%d)\n", PORT_NUM, ret);

    /* Run your DPDK application here */

    return 0;
}

在上述代码中，rte_eth_dev_configure函数用于配置DPDK端口，其中rxmode和txmode字段分别设置了接收和发送模式，包括最大接收包长度和多队列发送模式；rte_eth_dev_adjust_mtu函数用于设置MTU值。需要注意的是，在调用rte_eth_dev_start函数之前必须完成DPDK端口的配置和MTU值的设置。