void benchmarkOne() throws IOException {
   for (int idx = 0; idx < opsPerThread; idx++) {
     if ((localNumOpsExecuted + 1) % statsOp.ugcRefreshCount == 0)
       nameNode.refreshUserToGroupsMappings();
     long stat = statsOp.executeOp(daemonId, idx, arg1);
     localNumOpsExecuted++;
     localCumulativeTime += stat;
   }
 }