/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <sys/queue.h>

#include <rte_common.h>
#include <rte_memory.h>
#include <rte_launch.h>
#include <rte_eal.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_cycles.h>
#include <rte_timer.h>
#include <rte_debug.h>

#define TIMER_RESOLUTION_CYCLES 20000000ULL /* around 10ms at 2 Ghz */

static struct rte_timer timer0;
static struct rte_timer timer1;

/* timer0 callback */
static void
timer0_cb(__attribute__((unused)) struct rte_timer *tim,
	  __attribute__((unused)) void *arg)
{
	static unsigned counter = 0;
	unsigned lcore_id = rte_lcore_id();

	printf("%s() on lcore %u\n", __func__, lcore_id);

	/* this timer is automatically reloaded until we decide to
	 * stop it, when counter reaches 20. */
	if ((counter ++) == 20)
		rte_timer_stop(tim);
}

/* timer1 callback */
static void
timer1_cb(__attribute__((unused)) struct rte_timer *tim,
	  __attribute__((unused)) void *arg)
{
	unsigned lcore_id = rte_lcore_id();
	uint64_t hz;

	printf("%s() on lcore %u\n", __func__, lcore_id);

	/* reload it on another lcore */
	hz = rte_get_timer_hz();
	lcore_id = rte_get_next_lcore(lcore_id, 0, 1);
	rte_timer_reset(tim, hz/3, SINGLE, lcore_id, timer1_cb, NULL);
}

static __attribute__((noreturn)) int
lcore_mainloop(__attribute__((unused)) void *arg)
{
	uint64_t prev_tsc = 0, cur_tsc, diff_tsc;
	unsigned lcore_id;

	lcore_id = rte_lcore_id();
	printf("Starting mainloop on core %u\n", lcore_id);

	while (1) {
		/*
		 * Call the timer handler on each core: as we don't
		 * need a very precise timer, so only call
		 * rte_timer_manage() every ~10ms (at 2Ghz). In a real
		 * application, this will enhance performances as
		 * reading the HPET timer is not efficient.
		 */
		cur_tsc = rte_rdtsc();
		diff_tsc = cur_tsc - prev_tsc;
		if (diff_tsc > TIMER_RESOLUTION_CYCLES) {
			rte_timer_manage();
			prev_tsc = cur_tsc;
		}
	}
}

int
main(int argc, char **argv)
{
	int ret;
	uint64_t hz;
	unsigned lcore_id;

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

	/* init RTE timer library */
	rte_timer_subsystem_init();

	/* init timer structures */
	rte_timer_init(&timer0);
	rte_timer_init(&timer1);

	/* load timer0, every second, on master lcore, reloaded automatically */
	hz = rte_get_timer_hz();
	lcore_id = rte_lcore_id();
	rte_timer_reset(&timer0, hz, PERIODICAL, lcore_id, timer0_cb, NULL);

	/* load timer1, every second/3, on next lcore, reloaded manually */
	lcore_id = rte_get_next_lcore(lcore_id, 0, 1);
	rte_timer_reset(&timer1, hz/3, SINGLE, lcore_id, timer1_cb, NULL);

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

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

	return 0;
}