Function latencyMode

app/redis-6.2.6/src/redis-cli.c:6850–6908

#define LATENCY_SAMPLE_RATE 10 /* milliseconds. */
#define LATENCY_HISTORY_DEFAULT_INTERVAL 15000 /* milliseconds. */
static void latencyMode(void) {
    redisReply *reply;
    long long start, latency, min = 0, max = 0, tot = 0, count = 0;
    long long history_interval =
        config.interval ? config.interval/1000 :
                          LATENCY_HISTORY_DEFAULT_INTERVAL;
    double avg;
    long long history_start = mstime();

    /* Set a default for the interval in case of --latency option
     * with --raw, --csv or when it is redirected to non tty. */
    if (config.interval == 0) {
        config.interval = 1000;
    } else {
        config.interval /= 1000; /* We need to convert to milliseconds. */
    }

    if (!context) exit(1);
    while(1) {
        start = mstime();
        reply = reconnectingRedisCommand(context,"PING");
        if (reply == NULL) {
            fprintf(stderr,"\nI/O error\n");
            exit(1);
        }
        latency = mstime()-start;
        freeReplyObject(reply);
        count++;
        if (count == 1) {
            min = max = tot = latency;
            avg = (double) latency;
        } else {
            if (latency < min) min = latency;
            if (latency > max) max = latency;
            tot += latency;
            avg = (double) tot/count;
        }

        if (config.output == OUTPUT_STANDARD) {
            printf("\x1b[0G\x1b[2K"); /* Clear the line. */
            latencyModePrint(min,max,avg,count);
        } else {
            if (config.latency_history) {
                latencyModePrint(min,max,avg,count);
            } else if (mstime()-history_start > config.interval) {
                latencyModePrint(min,max,avg,count);
                exit(0);
            }
        }

        if (config.latency_history && mstime()-history_start > history_interval)
        {
            printf(" -- %.2f seconds range\n", (float)(mstime()-history_start)/1000);
            history_start = mstime();
            min = max = tot = count = 0;
        }
        usleep(LATENCY_SAMPLE_RATE * 1000);
    }