private long getTotalDecompressionTimeOnVm(final VM vm, final String regionName) {
    return (Long) vm.invoke(new SerializableCallable() {
      @Override
      public Object call() throws Exception {
        if (null == regionName) {
          return getTotalDecompressionTime();
        } else {
          return getTotalDecompressionTime(regionName);
        }
      }
    });
  }
Returns the total decompression time stat for a virtual machine.

@param vm a virtual machine.
@param regionName a region. Indicates the whole cache when null.
geode-core/src/distributedTest/java/org/apache/geode/internal/compression/CompressionStatsDUnitTest.java