DPDK学习笔记<4>源代码分析（1）

源代码分析（1）helloworld

源代码：

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#include
#include
#include
#include
#include

#include
#include
#include
#include
#include
#include
#include

static int
lcore_hello(__attribute__((unused)) void *arg)
{
unsigned lcore_id;
lcore_id = rte_lcore_id();
printf("hello from core %u\n", lcore_id);
return 0;
}

int
main(int argc, char **argv)
{
int ret;
unsigned lcore_id;

ret = rte_eal_init(argc, argv);
if (ret < 0)
rte_panic("Cannot init EAL\n");

/* call lcore_hello() on every slave lcore */
RTE_LCORE_FOREACH_SLAVE(lcore_id) {
rte_eal_remote_launch(lcore_hello, NULL, lcore_id);
}

/* call it on master lcore too */
lcore_hello(NULL);

rte_eal_mp_wait_lcore();
return 0;
}

分析：

helloworld为dpdk的入门样例程序，程序的编写和系统编程一样都是从main函数作为入口函数。

rte_eal_init()启动基础运行环境，该函数完成的工作比较复杂，读取入口参数，解析并保存DPDK运行的系统信息，并根据这些信息构建包处理的运行环境。

配置初始化

内存初始化

内存池初始化

队列初始化

警告初始化

中断初始化

PCI初始化

定时器初始化

…………

使用DPDK这些操作已经被EAL封装，如果需要进行深度定制二次开发，则需要进一步的研究。

RTE_LCORE_FOREACH_SLAVE(lcore_id) {
rte_eal_remote_launch(lcore_hello, NULL, lcore_id);
}

DPDK面向多核设计，程序试图独占运行在逻辑核（lcore）上，RTE_LCORE_FOREACH_SLAVE遍历EAL指定的可用逻辑核，然后在每个逻辑核上执行被指定的线程，本文中为

lcore_hello。（大家可以执行设计lcore_hello）。