How to Baseline a Web application using Jmeter

Question

I want to Baseline my application .It is having two transactions "Place Order" and "Add A Product To Favorites".. Both of these transactions follow the same navigation route mostly. For the - Place Order Business Transaction the steps are Land on Login Page .. Login..Add To Cart..Checkout..Place Order. For the - Add A Product to favorites Business Transaction, the steps are : Land on Login page..Login....Add To Cart...Add to favorites. I want to run Test and see the consistent response time the application gives at a particular throughput. I have the below queries.

If I create Add to Favorites scenario as a Thread Group with 4 samplers and Place Order Scenario with 5 samplers(as given by the steps mentioned ), should I add a throughput Shaping Timer separately for the individual Thread Group and if so what would be the Throughput parameters that I should give like RPS settings. My application has the following Max response time and avg response time for a normal Load(i.e with no queue wait time since I collected the response times by just running a single thread so that the Wait time component is Zero) .N.B L I have not added the think time for simplicity sake and also the response times are bit too costly since the backend ERPs are legacy systems.

So, the Thread Group that I will create for "Place Order" has http samplers below with their respective response times for a 1 user load:

1. Land on Login page - 6074 ms (avg 4492 ms)
2. Login using Credentials - 2549 ms (avg is 631 ms)
3. Add To Cart - 1553 ms (avg is 304 ms)
4. Land on Cart page: 47044 ms (Avg: 15901 ms)
5. Place Order : 19126 ms (avg is 17110 ms)
6. Logout : 4801 ms (avg is 2706 ms)

Below are my queries:

1. With the above response timings what is the max throughput i.e Place Order transactions that I can achieve so that I can set that as the TPS parameter in the Throughput shaping graph plugin and then run a load test. Please can somebody explain the calculation process to arrive at that value.

2. The same samplers (i.e Land on Login Page and Login and add to cart ) is used in multiple Thread Groups like the Place order Business Scenario above and the Add A Product To Favorite Business transaction . So my question is, if different Thread groups are going to pound the same Login Controller Servlet/Add to Cart Servlet (my app is a J2EE app) so how to take that into consideration so that the queue generated for the Login sampler will not affect the TPS to be achieved by place order Business scenario and the other Business scenarios that use the login sampler transaction since we will be running both the Thread groups.(One for Place Order and One thread Group for Add to favorites) while running the Load test

3. How to set the concurrency for a Thread group; say the Place Order Transaction .I have this question since we need to know the max response time. Hence should I add the entire response times of all the samplers in the Thread group and multiply by the TPS that we calculated and divide by 1000 .Please explain the logic in this case too.

Answer 1

1. Nobody apart from you can answer, from your numbers we can state that 1 user is capable of executing 1 Place Order request in 19 seconds or 3 Place Order requests per minute. If you add one more user there could be 2 cases:

   1. Response time remains the same. In this case you will be able to execute 6 requests per minute with 2 users, 9 requests per minute with 3 users, etc.

   2. Respons time increases. In this case you will NOT be able to execute 6 request per minute with 2 users due to performance bottleneck.

   Check out What is the Relationship Between Users and Hits Per Second? article for more details.

2. I don't think you should be measuring various business use cases separately, well-behaved load test should represent real-live application usage as close as possible and in reality it is more than possible than one user creates and order while other users are logging in. However if you explicitly need to test order creation separately you can perform login in setUp Thread Group and then pass the authentication context (in majority of cases it is a set of Cookies) to the main Thread Group where the order creation takes place using i.e. Inter-Thread Communication Plugin

3. You don't need to know response time, you need to provide enough virtual users in order to conduct the required load (given the application is capable of handling it), consider using Concurrency Thread Group which can kick off extra threads if the current amount is not enough for maintaining the desired throughput. It can be connected with the Throughput Shaping Timer via Feedback function.