presto-jmx/src/main/java/io/prestosql/plugin/jmx/JmxPeriodicSampler.java/JmxPeriodicSampler/roundToPeriod
class JmxPeriodicSampler:    private long roundToPeriod(long millis)
    {
        return ((millis + period / 2) / period) * period;
    }