As per the Documentation - "Of course, if the server is not able to handle such a load, the throughput will be lower." How is this behavior handled and throughput calculated?
Suppose I set the target throughput as 1500/min but my system could handle only 1000/min, what kind of feedback behavior is expected by JMeter and how is the total throughput affected?
Will the JMeter still try to achieve 1500/min with higher error rate (for failed requests) or JMeter shoots the throughput to 1500/min but gradually comes back near to 1000/min based on certain factors like error rate? If yes, what are the factors determining this step-down, any insight/reference to understand this step-down behavior?
Either you do not have enough threads in the test plan to achieve your desired TPS or your application response time is higher.
The total number of requests you will be able to make through JMeter depends on your application response time.
So you will need at least 25 threads to achieve 1500/min if your average response time is 1 second (assuming there is only 1 request).
If throughput isn't increasing even after providing with enough threads but the response time increasing and some of your requests got failed, then this indicates the performance bottleneck!
JMeter cannot send requests faster than your application is capable of responding. If your application can only serve 1000 requests per minute - you will have 1000 requests per minute no matter how many threads you have in the Thread Group or how many requests per minute you specify in the Constant Throughput Timer.
Also be aware that:
Constant Throughput Timer can only pause the Threads, it will not do anything if the current amount of threads is not enough to reach/maintain the desired throughput
Constant Throughput Timer is accurate enough on minute level so consider choosing proper ramp-up settings otherwise you can stress your application during first minute of your test
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?
How can I find out maximum throughput my application can achieve within sla of 1 sec as response time.i.e response time should be within 1 sec
Currently I am using throughput controller and setting up the required throughput per minute, but I need to know max throughput my application can deliver with average response time less then 1 sec.
Using Thread Group, set Number of Threads (users) to some big number and set rump-up period to e.g.: 600s (10min)
Jmeter will slowly increase throughput and you can monitor Max response time in Summary report (column Max) - when it starts reaching 1s, you can read your desired Throughput (in Throughput column) Then I recommend set this number to Number of threads, decrease rump-up and run test for couple of hours.
Avoid using sleeps in your loop in JMeter. Beware of cache at application side. Monitor Faults in Error columns and check system health on both sides (CPU,mem,IO,Netw,...)
Please note that Throughput Controller does not control the throughput.
Following is from the JMeter official site.
This controller is badly named, as it does not control throughput.
Please refer to the Constant Throughput Timer for an element that can
be used to adjust the throughput.
You may use plugin Throughput Shaping Timer if you want to have controlled throughput changing with the time.
Change the threads (virtual users) and throughput to check the maximum through that can be handled by the server.
Use Duration Assertion to check the response time of each desired sampler.
Just don't limit JMeter's throughput.
Start with 1 thread (virtual user) and gradually increase the load until you see response times exceeding 1 second (you can use i.e. AutoStop Listener plugin for automatically stopping the test when average response becomes higher than 1 second)
Once done you can look into Transactions per Second and Server Hits per Second, it will give you the number you're looking for.
I am trying to stress test my server.
To do so I am using Jmeter and here is my set up:
I use
my Setup
Thread: 1000
schedule for 3 mins
So as you see I keep going with 1000 thread for a period of 3 mins.
But when I look at the throughput I only get around 230 per second
results
So what should I do to increase the through put to for example 1000000 per second? How come increasing the thread which I assume means more load does not increase throughput?
According to 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).
Throughput explicitly relies on the application response time. Looking into your results, the average response time is 3.5 seconds therefore you will not get more than 1000 / 3.5 = 285 requests per second
Theoretically you could use Throughput Shaping Timer and Concurrency Thread Group combination, this way JMeter will kick off extra threads if the current amount is not enough to reach/maintain the desired throughput, however looking into 8.5% error rate and maximum response time for your application > 2 minutes my expectation is that you will not be able to get more throughput because most probably your application is overloaded and cannot respond faster.
Throughput measures the number of transactions or requests that can be made in a given period of time. basically, it lists the number of requests server managed to serve in a given time period. Throughput value depends on lot of factors and maybe your application under test not able to cater the expected load.
So with 1000 threads, you can't expect a 1000 throughput.
It's up to you to find out how much throughput your application can handle. For that maybe you need to do different optimizations on your side like optimize your script, distribute load via JMeter execution, increase theard count,...etc
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 have a Thread-Group that runs a set amount of time and control the throughput through a Constant Throughput Timer. So in theory, about the same number of Samples should be processed, regardless of the number of Threads deployed.
E.g. ignoring warmup/down the test runs for 10 min with a throughput of 5 Threads/s, therefore roughly 3000 Samples should be processed.
How does changing the number of Threads effect the test?
Ignoring the startup/shutdown period, will the results of the test differ if I have 1000 or 2000 Threads, if only 100 can be completed in a minute?
How can I work out the number of Threads required, given the throughput?
Constant Throughput Timer
Can only pause threads to match the given throughput value. It won't kick off more threads if you don't have enough defined at Thread Group level.
Is accurate enough on minute level. If your test lasts less than a minute - consider other options like playing with ramp-up.
For more information check out How to use JMeter's Throughput Constant Timer
Also it might be better and easier to use Throughput Shaping Timer available via JMeter Plugins project which extends CTT capabilities and provides easy understandable visual view of expected throughput
The number of threads will impact results if your server faces slowdowns.
If so and you don't have enough threads then you will not be injecting the expected load and end up with less transactions performed.
If you have more, then the target load will be injected potentially leading to server crash.
Finally be aware that if you don't make your test last enough, jmeter will potentially inject more than expected because it needs some time to reach the expected req/s , it will inject more at begining.