Understanding Summary Report in Jmeter

The summary report shows values about the measurement Jmeter has done while calling the same page as if many users are calling the page. It gives the result in tabular format which you can save as .csv file.

These are some main headings in the summary result listener. Lets understand them in detail:


Summary Report:
In the above image you can see in the red lined box: Label, Samples, Average, Max, Min, Std.Dev, Error%, Throughput, KB/Sec, Avg.Bytes.

Label: In the label section you will able to see all the recorded http request, during test run or after test run.

Samples: Samples denote to the number of http request ran for given thread. Like we have one http request and we run it with 5 users, than the number of samples will be 5x1=5.
Same if the sample ran two times for the single user, than the number of samples for 5 users will be 5x2=10.

Average: Average is the average response time for that particular http request. This response time is in millisecond. Like in the image you can see for first label, in which the number of sample is 4 because that sample run 2 time for single user and i ran the test with 2 user. So for 4 samples the average response time is 401 ms.

Min: Min denotes to the minimum response time taken by the http request. Like for the above image the minimum response time for first four samples is 266 ms. It means one http request responded in 266 ms out of four samples.

Max: Max denotes to the maximum response time taken by the http request. Like for the above image the maximum response time for first four samples is 552 ms. It means one http request responded in 552 ms out of four samples.

Std.Deviation: This shows how many exceptional cases were found which were deviating from the average value of the receiving time. The lesser this value more consistent the time pattern is assumed.

Error %: This denotes the error percentage in samples during run. This error can be of 404(file not found), or may be exception or any kind of error during test run will be shown in Error %. In the above image the error % is zero, because all the requests ran successfully.

Throughput: The throughput is the number of requests per unit of time (seconds, minutes, hours) that are sent to your server during the test.

Distributed load testing in JMeter

What is distributed load testing?
Distributed load testing is the process using which multiple systems are used for simulating load of large number of users. In JMeter this is achieved by creating a Master- Slave configuration.

Why it is required?
The reason of using more than one system for load testing is the limitation of single system to generate large number of threads (users).

What other options do we have?
Apart from using distributed load testing we can perform load testing over cloud also. Load testing on cloud (like Amazon’s EC2) has several advantages- easy scalability, no maintenance, fast deployment and no artificial network bottlenecks.
Another alternative is Blazemeter which is a cloud based service compatible with Apache JMeter. It generates large amount of instant load and provide very comprehensive reporting and analysis features.
Also, we can perform distributed load testing on cloud, in which multiple machines on cloud can be used for generating large amount of load.


Distributed Load Testing using JMeter:
For distributed load testing we need to create Master-slave configuration wherein Master will control all the slaves and collect the test results. To make the system work firewall needs to be turned off and all the systems need to be in same subnet.
Also, preferably all the systems need to use same version of JMeter and Java.


1. First of all we need to start the jmeter-server.bat in the slave systems. For this just go to the bin folder inside JMeter home directory and run the batch file jmeter-server.bat(for windows) or jmeter-server (for linux).
2. Now on the master system open the properties file jmeter.properties and edit theremote_hosts entry. Remove the loopback address’s value (127.0.0.1) for the remote_host entry and specify the IP addresses of all the slave systems separated by commas.

3. We just need to Remote start all the slave machines remotely in JMeter. For this just open JMeter on the Master machine (for which properties file is just edited). Open your test script and remote start all the nodes.