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path: root/lib/librte_eal/linuxapp/eal/eal_thread.c
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/*-
 *   BSD LICENSE
 * 
 *   Copyright(c) 2010-2012 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.
 * 
 *  version: DPDK.L.1.2.3-3
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <pthread.h>
#include <sched.h>
#include <sys/queue.h>

#include <rte_debug.h>
#include <rte_atomic.h>
#include <rte_launch.h>
#include <rte_log.h>
#include <rte_memory.h>
#include <rte_memzone.h>
#include <rte_per_lcore.h>
#include <rte_tailq.h>
#include <rte_eal.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>

#include "eal_private.h"
#include "eal_thread.h"

RTE_DEFINE_PER_LCORE(unsigned, _lcore_id);

/*
 * Send a message to a slave lcore identified by slave_id to call a
 * function f with argument arg. Once the execution is done, the
 * remote lcore switch in FINISHED state.
 */
int
rte_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;

	lcore_config[slave_id].f = f;
	lcore_config[slave_id].arg = arg;

	/* send message */
	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 */
	n = 0;
	do {
		n = read(s2m, &c, 1);
	} while (n < 0 && errno == EINTR);

	if (n <= 0)
		rte_panic("cannot read on configuration pipe\n");

	return 0;
}

/* set affinity for current thread */
static int
eal_thread_set_affinity(void)
{
	int s;
	pthread_t thread;

/*
 * According to the section VERSIONS of the CPU_ALLOC man page:
 *
 * The CPU_ZERO(), CPU_SET(), CPU_CLR(), and CPU_ISSET() macros were added
 * in glibc 2.3.3.
 *
 * CPU_COUNT() first appeared in glibc 2.6.
 *
 * CPU_AND(),     CPU_OR(),     CPU_XOR(),    CPU_EQUAL(),    CPU_ALLOC(),
 * CPU_ALLOC_SIZE(), CPU_FREE(), CPU_ZERO_S(),  CPU_SET_S(),  CPU_CLR_S(),
 * CPU_ISSET_S(),  CPU_AND_S(), CPU_OR_S(), CPU_XOR_S(), and CPU_EQUAL_S()
 * first appeared in glibc 2.7.
 */
#if defined(CPU_ALLOC)
	size_t size;
	cpu_set_t *cpusetp;

	cpusetp = CPU_ALLOC(RTE_MAX_LCORE);
	if (cpusetp == NULL) {
		RTE_LOG(ERR, EAL, "CPU_ALLOC failed\n");
		return -1;
	}

	size = CPU_ALLOC_SIZE(RTE_MAX_LCORE);
	CPU_ZERO_S(size, cpusetp);
	CPU_SET_S(rte_lcore_id(), size, cpusetp);

	thread = pthread_self();
	s = pthread_setaffinity_np(thread, size, cpusetp);
	if (s != 0) {
		RTE_LOG(ERR, EAL, "pthread_setaffinity_np failed\n");
		CPU_FREE(cpusetp);
		return -1;
	}

	CPU_FREE(cpusetp);
#else /* CPU_ALLOC */
	cpu_set_t cpuset;
	CPU_ZERO( &cpuset );
	CPU_SET( rte_lcore_id(), &cpuset );

	thread = pthread_self();
	s = pthread_setaffinity_np(thread, sizeof( cpuset ), &cpuset);
	if (s != 0) {
		RTE_LOG(ERR, EAL, "pthread_setaffinity_np failed\n");
		return -1;
	}
#endif
	return 0;
}

void eal_thread_init_master(unsigned lcore_id)
{
	/* set the lcore ID in per-lcore memory area */
	RTE_PER_LCORE(_lcore_id) = lcore_id;

	/* set CPU affinity */
	if (eal_thread_set_affinity() < 0)
		rte_panic("cannot set affinity\n");
}

/* 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;

	thread_id = pthread_self();

	/* retrieve our lcore_id from the configuration structure */
	RTE_LCORE_FOREACH_SLAVE(lcore_id) {
		if (thread_id == lcore_config[lcore_id].thread_id)
			break;
	}
	if (lcore_id == RTE_MAX_LCORE)
		rte_panic("cannot retrieve lcore id\n");

	RTE_LOG(DEBUG, EAL, "Core %u is ready (tid=%x)\n",
		lcore_id, (int)thread_id);

	m2s = lcore_config[lcore_id].pipe_master2slave[0];
	s2m = lcore_config[lcore_id].pipe_slave2master[1];

	/* set the lcore ID in per-lcore memory area */
	RTE_PER_LCORE(_lcore_id) = lcore_id;

	/* set CPU affinity */
	if (eal_thread_set_affinity() < 0)
		rte_panic("cannot set affinity\n");

	/* read on our pipe to get commands */
	while (1) {
		void *fct_arg;

		/* wait command */
		n = 0;
		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 */
		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");

		if (lcore_config[lcore_id].f == NULL)
			rte_panic("NULL function pointer\n");

		/* call the function and store the return value */
		fct_arg = lcore_config[lcore_id].arg;
		ret = lcore_config[lcore_id].f(fct_arg);
		lcore_config[lcore_id].ret = ret;
		rte_wmb();
		lcore_config[lcore_id].state = FINISHED;
	}

	/* never reached */
	/* pthread_exit(NULL); */
	/* return NULL; */
}