Function serverCron

app/redis-6.2.6/src/server.c:2046–2277

 */

int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
    int j;
    UNUSED(eventLoop);
    UNUSED(id);
    UNUSED(clientData);

    /* Software watchdog: deliver the SIGALRM that will reach the signal
     * handler if we don't return here fast enough. */
    if (server.watchdog_period) watchdogScheduleSignal(server.watchdog_period);

    /* Update the time cache. */
    updateCachedTime(1);

    server.hz = server.config_hz;
    /* Adapt the server.hz value to the number of configured clients. If we have
     * many clients, we want to call serverCron() with an higher frequency. */
    if (server.dynamic_hz) {
        while (listLength(server.clients) / server.hz >
               MAX_CLIENTS_PER_CLOCK_TICK)
        {
            server.hz *= 2;
            if (server.hz > CONFIG_MAX_HZ) {
                server.hz = CONFIG_MAX_HZ;
                break;
            }
        }
    }

    run_with_period(100) {
        long long stat_net_input_bytes, stat_net_output_bytes;
        atomicGet(server.stat_net_input_bytes, stat_net_input_bytes);
        atomicGet(server.stat_net_output_bytes, stat_net_output_bytes);

        trackInstantaneousMetric(STATS_METRIC_COMMAND,server.stat_numcommands);
        trackInstantaneousMetric(STATS_METRIC_NET_INPUT,
                stat_net_input_bytes);
        trackInstantaneousMetric(STATS_METRIC_NET_OUTPUT,
                stat_net_output_bytes);
    }

    /* We have just LRU_BITS bits per object for LRU information.
     * So we use an (eventually wrapping) LRU clock.
     *
     * Note that even if the counter wraps it's not a big problem,
     * everything will still work but some object will appear younger
     * to Redis. However for this to happen a given object should never be
     * touched for all the time needed to the counter to wrap, which is
     * not likely.
     *
     * Note that you can change the resolution altering the
     * LRU_CLOCK_RESOLUTION define. */
    unsigned int lruclock = getLRUClock();
    atomicSet(server.lruclock,lruclock);

    cronUpdateMemoryStats();

    /* We received a SIGTERM, shutting down here in a safe way, as it is
     * not ok doing so inside the signal handler. */