Test

• standalone mongod
• test with following benchRun script:

  var run = function() {
          var d = db.getSiblingDB("test");
          d.foo.insert({_id:1,a:0});
  
          res = benchRun( {
                  ops : [{
                                  ns : "test.foo",
                                  op : "update" ,
                                  query: {_id: 1},
                                  update : { $inc: {a: 1} } ,
                                  w: 1,
                                  writeCmd : true }],
                  seconds : 60,
                  totals : true,
                  writeCmd : true,
                  w: 1,
                  parallel : 40
          });
  
          return res
  }
  
  var s = db.serverStatus();
  var v = db.serverBuildInfo();
  
  print("Version: " + v.version)
  print("git version: " + v.gitVersion)
  if ( s.storageEngine !== undefined) {
      print("storageEngine: " + db.serverStatus().storageEngine.name)
  }
  print("Update RPS: " + run().update);
  

Results:

• the throughput from both WT and mmapv1 is slower than that of 2.6.7

  test	rc9 + wt	rc9 + mmapv1	2.6.7 + mmapv0
  contenedUpdate (update with 40 thread)	23082	22061	25975
  update with 1 thread	8947	10849	10816

Observation

• WT update is slow, this probably related how update is done with WT. With single thread update, it is 17.3% slower than 2.6.7, and 11.2% with 40 thread update
• mmapv1 is slower when there is contention, and in par with mmapv0 (single thread update)