Track my Performance Data with WebDriver test by MongoDB

In my WebDriver test, I will always track performance data during automation test on daily bases, it helps to reuse automation scripts which QA team donated to track slowness cases, and guarantee the test coverage very well.
Here is a sample tracking diagram (X-axis: Date, Y-axis: Response time):

Meanwhile, the data is End-End response time,not only back-end html generation time, which load testing tool usually measures.

Testing Code:

MongoDBReader conn = new MongoDBReader();  
WebDriver driver = new FirefoxDriver();  

long starttime = new Date().getTime();  
driver.get("http://www.google.com/");  
conn.InstertPermLog(starttime, "Landing_Page");  

driver.close();  

MongoDBReader source code:

 import java.net.UnknownHostException;  
 import java.util.Date;  
 import java.text.DateFormat;  
 import java.text.SimpleDateFormat;  
 import com.mongodb.BasicDBObject;  
 import com.mongodb.DB;  
 import com.mongodb.DBCollection;  
 import com.mongodb.Mongo;  
 import com.mongodb.MongoException;  
 /* sample usage  
  * MongoDBReader conn = new MongoDBReader();  
  * ...  
  * long starttime = new Date().getTime();  
  * driver.get("http://www.google.com/");  
  * conn.InstertPermLog(starttime, "Landing_Page");  
  */  
 public class MongoDBReader {  
      private DB db;  
      private DBCollection coll;  
      public MongoDBReader(String hostname) throws UnknownHostException, MongoException{  
           // Connect to Mongo DB server  
           Mongo m = new Mongo( hostname );  
           // Get Mongo DB Connection  
           db = m.getDB("perfdb");  
           // Prepare Collection  
           coll = db.getCollection("perfTestColl");  
      }  
      public MongoDBReader() throws UnknownHostException, MongoException {  
           //Connect to the localhost MongoDB by Default  
           String hostname = "localhost";  
           // Connect to Mongo DB server  
           Mongo m = new Mongo( hostname );  
           // Get Mongo DB Connection  
           db = m.getDB("perfdb");  
           // Prepare Collection  
           coll = db.getCollection("perfTestColl");  
      }  
      public DB getDB(){  
           return db;  
      }  
      public DBCollection getCollection(){  
           return coll;  
      }  
      public void InstertPermLog(long startTime, String transactionName){  
           long endtime = new java.util.Date().getTime();  
           long responsetime = endtime - startTime;  
           DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.S");  
        Date date = new Date();  
           BasicDBObject doc = new BasicDBObject();  
           doc.put("TimeStamp", dateFormat.format(date));  
           doc.put("Rtime", responsetime);  
           doc.put("transaction", transactionName);  
           coll.insert(doc);  
      }  
 }  

MongoDB Shell console:

> db.perfTestColl.find();

{ "_id" : ObjectId("4d078fbb3599030f8a412be1"), "TimeStamp" : "2010/12/14 23:39:

39.546", "Rtime" : NumberLong(4609), "transaction" : "Landing_Page" }

{ "_id" : ObjectId("4d078fc33599030f8b412be1"), "TimeStamp" : "2010/12/14 23:39:

47.953", "Rtime" : NumberLong(1641), "transaction" : "Landing_Page" }

{ "_id" : ObjectId("4d078fcb3599030f8c412be1"), "TimeStamp" : "2010/12/14 23:39:

55.578", "Rtime" : NumberLong(1360), "transaction" : "Landing_Page" }