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;
}