DPDK学习笔记<4>源代码分析（1）

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最新推荐文章于 2025-07-11 00:01:35 发布

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分类专栏： DPDK专题文章标签： c语言 linux 源代码 helloworld

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本文介绍DPDK入门程序helloworld的源代码分析，重点讲解rte_eal_init()函数的作用及初始化流程，包括配置、内存、PCI等初始化过程，并展示了如何在多核环境下运行指定线程。

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源代码分析（1）helloworld

源代码：

/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#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）。