private synchronized void update(long gcMonitorRunTimeNanos,
        long totalGcTimeNanos, int inGcTimePercentage) {
      this.gcMonitorRunTimeNanos = gcMonitorRunTimeNanos;
      this.totalGcTimeNanos = totalGcTimeNanos;
      this.gcTimePercentage = inGcTimePercentage;
    }
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