void setValues(long tsNanos, long gcPauseNanos) {
      this.tsNanos = tsNanos;
      this.gcPauseNanos = gcPauseNanos;
    }
Returns the percentage (0..100) of time that the JVM spent in GC pauses
within the observation window of the associated GcTimeMonitor.
common/src/java/org/apache/hadoop/hive/common/GcTimeMonitor.java