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dpdk中采用多核编程代替多线程模型，详细分析如下：在环境初始化函数rte_eal_init的最后有下面这段code#遍历系统中所有的cpuRTE_LCORE_FOREACH_SLAVE(i) {		/*		 * create communication pipes between master thread		 * and children		 */		#创建两个pipe，用于通知开始执行线程		if (pipe(lcore_config[i].pipe_master2slave) < 0)			rte_panic("Cannot create pipe\n");		if (pipe(lcore_config[i].pipe_slave2master) < 0)			rte_panic("Cannot create pipe\n");		lcore_config[i].state = WAIT;		/* create a thread for each lcore */		#为每个核创建一个线程，线程的回调函数是eal_thread_loop		ret = pthread_create(&lcore_config[i].thread_id, NULL,				     eal_thread_loop, NULL);		if (ret != 0)			rte_panic("Cannot create thread\n");		#修改线程的name		/* Set thread_name for aid in debugging. */		snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN,			"lcore-slave-%d", i);		ret = rte_thread_setname(lcore_config[i].thread_id,						thread_name);		if (ret != 0)			RTE_LOG(DEBUG, EAL,				"Cannot set name for lcore thread\n");	}这里我们来具体看看回调函数eal_thread_loop/* main loop of threads */__attribute__((noreturn)) void *eal_thread_loop(__attribute__((unused)) void *arg){	char c;	int n, ret;	unsigned lcore_id;	pthread_t thread_id;	int m2s, s2m;	char cpuset[RTE_CPU_AFFINITY_STR_LEN];	#得到当前的线程id	thread_id = pthread_self();	#将这个线程绑定在这个cpu上	/* set CPU affinity */	if (eal_thread_set_affinity() < 0)		rte_panic("cannot set affinity\n");	ret = eal_thread_dump_affinity(cpuset, RTE_CPU_AFFINITY_STR_LEN);	RTE_LOG(DEBUG, EAL, "lcore %u is ready (tid=%p;cpuset=[%s%s])\n",		lcore_id, thread_id, cpuset, ret == 0 ? "" : "...");	/* read on our pipe to get commands */	while (1) {		void *fct_arg;		#开始等待通过pipe发过来执行的命令		/* wait command */		do {			n = read(m2s, &c, 1);		} while (n < 0 && errno == EINTR);		if (n <= 0)			rte_panic("cannot read on configuration pipe\n");		lcore_config[lcore_id].state = RUNNING;		/* send ack */		#回复即将开始执行线程		n = 0;		while (n == 0 || (n < 0 && errno == EINTR))			n = write(s2m, &c, 1);		if (n < 0)			rte_panic("cannot write on configuration pipe\n");				/* call the function and store the return value */		fct_arg = lcore_config[lcore_id].arg;		#开始执行在这个核上的函数，并传递参数		ret = lcore_config[lcore_id].f(fct_arg);		lcore_config[lcore_id].ret = ret;		rte_wmb();		#设置flag 表示已经执行完成，开始下一次等待		lcore_config[lcore_id].state = FINISHED;	}}从这里知道所谓的多核编程就是每个核上有一个thread，平时这个thread处于sleep状态，要是有人通过pipe发送信号则开始执行这个核上的函数。那下来我们看看如何给这个线程发送命令开始执行呢？答案是通过下面这个函数进行	rte_eal_mp_remote_launch(sync_func, NULL, SKIP_MASTER);	intrte_eal_mp_remote_launch(int (*f)(void *), void *arg,			 enum rte_rmt_call_master_t call_master){	int lcore_id;	int master = rte_get_master_lcore();	/* check state of lcores */	#如果当前核上的线程不是wait状态说明正在执行其他任务则退出	RTE_LCORE_FOREACH_SLAVE(lcore_id) {		if (lcore_config[lcore_id].state != WAIT)			return -EBUSY;	}	/* send messages to cores */	#发送信号给所有的核	RTE_LCORE_FOREACH_SLAVE(lcore_id) {		rte_eal_remote_launch(f, arg, lcore_id);	}	return 0;}intrte_eal_remote_launch(int (*f)(void *), void *arg, unsigned slave_id){	int n;	char c = 0;	int m2s = lcore_config[slave_id].pipe_master2slave[1];	int s2m = lcore_config[slave_id].pipe_slave2master[0];	if (lcore_config[slave_id].state != WAIT)		return -EBUSY;	#保存在这个核上要执行的函数f和其参数arg	lcore_config[slave_id].f = f;	lcore_config[slave_id].arg = arg;	/* send message */	#开始发送命令开始执行任务	n = 0;	while (n == 0 || (n < 0 && errno == EINTR))		n = write(m2s, &c, 1);	if (n < 0)		rte_panic("cannot write on configuration pipe\n");	/* wait ack */	#等待回复	do {		n = read(s2m, &c, 1);	} while (n < 0 && errno == EINTR);	if (n <= 0)		rte_panic("cannot read on configuration pipe\n");	return 0;}

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