examples/timer/main.c

/* 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;
}