I'm doing performance testing on an app that does transactions.
I have 25 threads but only 5 unique IDs.
Here's my problem:
To avoid concurrency issue, I want to limit the number of requests being made during a buy/sell transaction to only 5 (cuz only 5 unique IDs). How do I achieve this in Jmeter?
Please be detailed in answer as i'm a total noobie. Thank you!!
You can limit the execution rate to the specified number of requests per unit of time using the following test elements:
Precise Throughput Timer
Constant Throughput Timer
Throughput Shaping Timer
All of them are capable of "pausing" JMeter threads to the specified throughput (# of requests per minute/second)
Use Synchronizing Timer
The purpose of the SyncTimer is to block threads until X number of threads have been blocked, and then they are all released at once.
With Number of Simultaneous Users to Group by as 5
Related
I have used the normal thread group of 40 threads,180000 of throughput, and expected TPS is 3000.., But , Resulted only 2750 tps., How can I improve the TPS?
I have tried the concurrency thread group along with the shaping timer combination..
Can u pls guide me..,Thanks in Advance.
TPS or the throughput is controlled by sending the required number of requests to the target server in a unit time (seconds, minutes, hours, etc)
It is not easy or good practice to control the throughput by changing the number of threads. When the server gets slow the throughput gets low and vice-versa.
You need to introduce delays when the server responds faster and introduce more threads when the server responds slower. It is not easy to achieve the desired throughput by setting the thread count.
Please note that
throughput will be lower if the server is not capable of handling it, or if other timers or time-consuming test elements prevent it.
JMeter has a number of ways to achieve the desired throughput by introducing delays to the requests.
Using Timers
Constant Throughput Timer
Precise Throughput Timer
Througput Shaping Timer
In the above cases, you need to ensure a sufficient number of threads are available to generate the required throughputs. This solution is not efficient if a large number of threads are created than the required number of threads.
The best approach would be the test should create additional threads on-demand and introduce delays between requests as required.
In JMeter, you can achieve this with Concurrency Thread Group along with the Throughput Shaping Timer.
This video demonstrate the use of the controllers.
First of all your application must be able to handle such a load. I don't know what your 180000 of throughput, stanza means,if you put it to the Constant Throughput Timer be aware that:
it is precise enough on "minute" level
it can only "pause" JMeter to "limit" its throughput to the given value
In general you can reach out 3000 TPS with 40 users only if 1 user will make 75 requests per second which means that your application response time should be below 75 milliseconds.
If response time will be higher - you won't be able to reach 3000 requests per second with 40 users.
Also JMeter should be able to send requests fast enough, so make sure to follow JMeter Best Practices and if this is not sufficient consider using Distributed Testing
More information: What is the Relationship Between Users and Hits Per Second?
I have tried with concurrent users thread group pairing with throughput timer , but the transactions were low , Is there any other way to achieve the above scenario
#dmitri
I happened to use this function ${__tstFeedback(throughput-timer,25,2500,100)} in my concurrent thread group still I what could see is not more than 200 transaction/sec
Concurency thread group setup
Throughput shaping timer
Transactions per sec
I always see this additional request added to my summary and aggregate reports results Concurrency Thread Group-ThreadStarter:
Concurrency Thread Group-ThreadStarter: 15034 27152 314 67905 17924.575009281336 0.5485566050286018 27.972210128343956 101.83185588876516 3.662355576998932 3727.836304376746
It might be a valid scenario depending on your application response time.
In order to be able to achieve 500 requests/second with 25 users each user needs to be able to execute 20 requests per second which means that your application response time needs to be 50 milliseconds or less.
If response time is above 50 milliseconds the number of requests per second will reduce proportionally.
If you have more than 1 request in your transaction - the response time constraint changes correspondingly like 2 requests - 25 milliseconds max, etc.
JMeter's Constant Throughput Timer can only capable of pausing the threads to limit the number of transactions per minute to the given value, if the current amount is not enough - it won't kick off extra threads. So it's your job to provide sufficient number of threads in the Thread Group
As the alternative you can consider going for Throughput Shaping Timer and Concurrency Thread Group combination, they can be connected via Feedback Function so if current number of threads is not enough to reach/maintain the desired throughput - more threads will be launched
I have created a performance test script as below. I am running 4 Thread Groups in parallel (Even though there are 14 Thread Groups, only 4 are enabled and I am running only those enabled 4 Thread Groups). I have used default Thread Groups.
I have used Flow Control Action to simulate the user think time and set it as 3 seconds.
My requirement is to achieve Throughput as 6.6/seconds. What is the best way to achieve it? Also, does user think time creates any impact on Throughput?
As per JMeter Glossary:
Throughput is calculated as requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server.
The formula is: Throughput = (number of requests) / (total time).
So basically throughput is the number of requests which JMeter was able to within test duration time frame. If you introduce artificial delay of 3 seconds - it will make the overall throughput lower
Other (and the main factor) is your application response time because JMeter waits for previous request to finish before executing new one so there could be 2 options:
The amount of threads in your Thread Groups is not sufficient to create the desired throughput. If this is the case - just add more threads (virtual users) in Thread Group(s)
The amount of threads in your Thread Groups is too high and you're getting higher throughput that you expect. If this is the case you can pause JMeter even more by adding Constant Throughput Timer and specifying the desired number of the requests per minute you want to have. If you need 6.6 requests per second it will mean 396 requests per minute
Also remember that JMeter itself must be able to send requests fast enough so make sure to follow JMeter Best Practices
My suggestion is to consider using the Arrivals Thread Group. This TG will allow you to configure the desire average throughput (ATP); the TG will instantiate the required threads needed to achieve the ATP goal.
As for the Think Time (TT), it should be a business requirement that emulates the pauses that users take when using the application in the real world.
Our requirement is to execute
1 user/thread, 10 requests/sec, Total requests = 10,000
With current Thread Properties not able to achieve.
Only one user/thread send 10 request/sec and total should be 10000 requests. Any other way to achieve this in Jmeter ?
Is following approach is correct ? We used Loop controller. So each request will repeat 10 times
You will be able to achieve 10 requests/second with 1 virtual user only if your response time will be 100 milliseconds. If response time will be more than 100 milliseconds - you will not be able to reach the desired load.
If your application fails to respond in 100 milliseconds time frame - most probably you've found a performance bottleneck and you can report this to your application developers.
If you have some time to investigate the issue you can try to provide more information, i.e. what is the average response time, what are minimum, maximum, quantiles, the actual number of requests per second, etc, all this information can be retrieved using Aggregate Report listener.
Normally when people are looking for the answer if the application under test can support X requests per second they use > 1 virtual user as load test should represent real life usage of the system under test and 1 thread (virtual user) isn't normally associated with performance testing and derivatives.
So probably you should reconsider your approach to testing and try increasing the number of threads (virtual users). The throughput can be controlled using Precise Throughput Timer or Constant Throughput Timer. However be aware that the above timers can only pause JMeter to slow it down to the desired throughput. Another approach is using Concurrency Thread Group and Throughput Shaping Timer combination, they can be connected using Feedback Function so JMeter will kick off extra threads in order to reach/maintain the desired number of requests per second.
You can install Concurrency Thread Group and Throughput Shaping Timer using JMeter Plugins Manager
I need to create a load test in which there's a maximum of 4 concurrent users per second. Then I need to repeat this for an hour.
Is there any way to achieve this in JMeter?
I have tried using this configuration:
Number of Threads: 4
Ramp-up period: 1
Loop count: Forever
Duration:3600
And to make sure that this run exactly for an hour I have also used a Runtime Controller with the same "3600" runtime value.
But these creates more concurrent users per second than what I need and besides it's also unlikely to have that many concurrent users as user usually take so time to think before they do something and this wasn't reflected in my configuration so also tried using Constant Throughput timer , but this only confused me more.
I'm sure I need to use the Constant Throughput Timer, but I don't have the faintest idea of how to do it in my case.
If a use the Constant Throughput Timer, how should I configure the Thread Properties (Number of threads, ramp-up period,loop count, schedule) ?
Do I really need to use a Runtime Controller, to ensure that the test plan runs exactly for an hour or is enough to specify a duration value of 3600?
Constant throughput timer allows you maintain throughput of your sever. (req/sec)
here requests are samplers. Threads are users/clients which are requesting server using samplers.
I hope this have cleared distinction between request and user i.e. sampler and thread.
Now Constant Throughput Timer works on sampler per minute basis. so for your requirement of 4 req per sec. it becomes 240 requests per minute.
and you want to maintain this throughput among all threads (if you have multiple thread groups) or among a single thread group if you have single thread group.
So JMeter engine will start all threads with given ramp-up but will allow only 4 samplers to executes at a given seconds i.e. only 4 request per second.
Thus throughput is achieved among all threads and you can continue this for a specified time using either ways,
Test duration
Runtime controller
I hope it cleared your confusion and solved the issue.