text: function benchrun_sub_insert(use_write_command) {
      t = db.benchrun_sub;
      t.drop();
      ops = [{op: "insert", ns: "test.benchrun_sub",
              doc: {x: { "#RAND_INT" : [ 0, 100 ] }},
              writeCmd: use_write_command,
              }];
  
      res = benchRun({parallel: 1,
                      seconds: 10,
                      ops : ops,
                      host: db.getMongo().host});
  
      assert.gt(res.insert, 0);
  
      t.find().forEach(function(doc) {
              var field = doc.x;
              assert.gte(field, 0);
              assert.lt(field, 100);
          }
      );
  }
  
  function benchrun_sub_update(use_write_command) {
      t = db.benchrun_sub;
      t.drop();
  
      ops = [{op: "update", ns: "test.benchrun_sub",
              query: {x: {"#RAND_INT": [0, 100]}},
              update: {$inc : {x : 1}},
              writeCmd: use_write_command}];
  
      for (var i = 0; i < 100; ++i) {
          t.insert({x: i});
      }
  
      res = benchRun({parallel: 1,
                      seconds: 10,
                      ops: ops,
                      host: db.getMongo().host});
  
      var field_sum = 0;
      t.find().forEach(function(doc) {
              field_sum += doc.x;
          }
      );
  
      assert.gt(field_sum, 4950); // 1 + 2 + .. 99 = 4950
  }
  
  function benchrun_sub_remove(use_write_command) {
      t = db.benchrun_sub;
      t.drop();
  
      ops = [{op: "remove", ns: "test.benchrun_sub",
              query: {x: {"#RAND_INT": [0, 100]}},
              writeCmd: use_write_command,
              }]
  
      for (var i = 0; i < 100; ++i) {
          t.insert({x: i});
      }
  
      res = benchRun({parallel: 1,
                      seconds: 10,
                      ops: ops,
                      host: db.getMongo().host});
  
      assert.eq(t.count(), 0);
  }
  
  benchrun_sub_insert(true);
  benchrun_sub_insert(false);
  benchrun_sub_update(true);
  benchrun_sub_update(false);
  benchrun_sub_remove(true);
  benchrun_sub_remove(false);
  