What is the difference between ramp up period 1 and ramp up period 0 ?
I have Thread count 10 and while giving ramp up 0 some of my cases making null pointer exception.With ramp up 1 its working fine. With ramp up 1 it means that within 1 second 10 users will start together. What will happen for ramp up 0?
If you set ramp-up as 0, all the threads will start at 1st second after the test has been started. If the ramp-up period is zero, JMeter will create all the threads at once and send out requests immediately.
You can use it while you require a sudden large influx of requests in your site.
Let's say you have set it up to use 10 threads and have a ramp-up period of 0 then when you start your test run it will make 10 requests at the exact same moment.
Related
I need to test an application can handle 500 users over the space on 1 hour. How long should I set the ramp up period for the specified amount of time and users?
It depends on what you're trying to achieve. There are no "strict" rules, no recommendations either.
As per JMeter documentation:
The ramp-up period tells JMeter how long to take to "ramp-up" to the full number of threads chosen. If 10 threads are used, and the ramp-up period is 100 seconds, then JMeter will take 100 seconds to get all 10 threads up and running. Each thread will start 10 (100/10) seconds after the previous thread was begun. If there are 30 threads and a ramp-up period of 120 seconds, then each successive thread will be delayed by 4 seconds.
Ramp-up needs to be long enough to avoid too large a work-load at the start of a test, and short enough that the last threads start running before the first ones finish (unless one wants that to happen).
Start with Ramp-up = number of threads and adjust up or down as needed.
So you can use 500 as ramp-up so all 500 users will be online in 500 seconds.
Other option is to set ramp-up period for 1st 30 minutes and next 30 minutes keep the load of 500 users.
The idea is to add users gradually so you could correlate increasing load with other metrics and KPIs like response time, number of transactions per second, number of errors, etc. so you could state where is the saturation point, where is the first bottleneck, etc.
More information: JMeter Ramp-Up Period: The Ultimate Guide
The ramp-up period, Is the time needed to start all the threads defined.
So, If you add 3600 with 500 Thread, This will mean a new thread will be launched every 7.2 seoconds, And the last one will start after 1h ( 3600 seconds)
If this is what you want, you can set Ramp up to 3600.
quote from official doc
The ramp-up period tells JMeter how long to take to "ramp-up" to the full number of threads chosen. If 10 threads are used, and the ramp-up period is 100 seconds, then JMeter will take 100 seconds to get all 10 threads up and running. Each thread will start 10 (100/10) seconds after the previous thread was begun.
Example:
`1. No of Threads = 100
Ramp-up time = 20, means every 1 second = 5 requests will be processed.
Loop Count =1
In the same time:
If i will do like below
No of Threads = 100
Ramp-up time = 1,
Loop Count =1`
And put Synchronization Timer : No of Simulated user to group = 5.
In this case as well, J meter process 5 requests at one time.
So what is the different logic between the above 2 concepts.
Considering case 1 where the
Number of threads = 100, Ramp-up time = 20 and loop count =1.
This means that for every one sec 5 threads will be induced.
Depending on the time taken for the response the test will run for at least 20 sec or more.
Considering case 2 where the
Number of threads = 100, Ramp-up=1, loop count=1 and
Adding Synchronization Timer with No of Simulated user to group = 5
A batch of 5 users will be added at once.
Both the tests don't take the same amount of time to complete.
In case 1, 5 users are distributed over a period of one sec. i.e. per 0.2 sec one user is added.
In case 2, 5 users are added to the active thread in one go.
To know more about Synchronizing Timer
To best understand the difference between the 2 use cases, increase the number of threads to 200 while keeping the remaining parameters as is. Then the difference can be noticed easily.
means every 1 second = 5 requests will be processed. Loop Count =1 - this is wrong, JMeter will start 5 threads each second, the processing time depends on application response time. The concurrency (number of requests at the same moment of time) is not guaranteed
A quote from JMeter documentation:
The ramp-up period tells JMeter how long to take to "ramp-up" to the full number of threads chosen. If 10 threads are used, and the ramp-up period is 100 seconds, then JMeter will take 100 seconds to get all 10 threads up and running. Each thread will start 10 (100/10) seconds after the previous thread was begun. If there are 30 threads and a ramp-up period of 120 seconds, then each successive thread will be delayed by 4 seconds.
Ramp-up needs to be long enough to avoid too large a work-load at the start of a test, and short enough that the last threads start running before the first ones finish (unless one wants that to happen).
Start with Ramp-up = number of threads and adjust up or down as needed.
See JMeter Ramp-Up - The Ultimate Guide article for more comprehensive explanation.
Synchronizing Timer guarantees that 5 requests will be executed at the same moment so in your 2nd scenario it would be sending requests in "batches" of 5. Normally people go for Synchronizing Timer to do some form of Spike Testing
I ran a test plan with 5 users for a total of 20 seconds and what I am not able to understand is what ramp-up period is in actual. Does it means that each user will get 4 seconds or 20 seconds will be used in total for 5 users?
If case 1 is true(4 second for each user) then the first thread should be completed in 4 seconds but it took 6 seconds to complete it and still the result is passed and next user gets executed? This gets much confusing. I need to clear my doubt as I am not able to find any answers from all the inputs that are available here
As per JMeter Thread Group Documentation:
Ramp-up Period
How long JMeter should take to get all the threads started. If there are 10 threads and a ramp-up time of 100 seconds, then each thread will begin 10 seconds after the previous thread started, for a total time of 100 seconds to get the test fully up to speed.
You have 5 users
if you set ramp-up period to 0 - all 5 users will start at once
if you set ramp-up period to 5 - JMeter will start with 1 user and will add an extra 1 user each second
if you set ramp-up period to 10 - JMeter will start with 1 user and will add an extra 1 user each 2 seconds
etc.
Once user is started it starts executing Samplers upside down (or according to Logic Controllers) when there are no more samplers to execute or loops to iterate - the thread is being shut down.
Check out JMeter Ramp-Up - The Ultimate Guide article for more information on configuring users arrival rate.
You might also be interested in Ultimate Thread Group which makes workload definition easier, moreover you will have a chart representing anticipated load. You can install Ultimate Thread Group using JMeter Plugins Manager
If you want threads not to effect test expected time then use instead Thread group's Loop Count as the number of repeatitions you need.
If you want/must use threads calculate ramp period time as
(test expected time + 1 second) * number of threads
I want to add 10 threads every 1 minute in my load testing.I put 300 seconds in my duration equivalent to 5 minutes. So the total threads are 50 after the test. Heres the config in the thread group. I am using JMeter GUI.
Threads: 10
Ramp up: 1
Duration: 300 seconds
Ramp up is the time in which all the users arrive on your tested application server.
In Thread Group documentation:
The ramp-up period tells JMeter how long to take to "ramp-up" to the full number of threads chosen. If 10 threads are used, and the ramp-up period is 100 seconds, then JMeter will take 100 seconds to get all 10 threads up and running. Each thread will start 10 (100/10) seconds after the previous thread was begun. If there are 30 threads and a ramp-up period of 120 seconds, then each successive thread will be delayed by 4 seconds.
Ramp-up needs to be long enough to avoid too large a work-load at the start of a test, and short enough that the last threads start running before the first ones finish (unless one wants that to happen).
Thread Group also provides a scheduler. Click the checkbox at the bottom of the Thread Group panel to enable/disable extra fields in which you can enter the duration of test, the startup delay, the start and end times of the run. You can configure Duration (seconds) and Startup Delay (seconds) to control the duration of each thread group and the after how much seconds it starts. When the test is started, JMeter will wait Startup Delay (seconds) before starting the Threads of the Thread Group and run for the configured Duration (seconds) time. Note those 2 options override the Start time and End time.
Set your Thread Group like this:
No. of Threads: 50
Ramp-up Time - 300sec (Since you want 10 users per min, 10*60*5= 300)
Loop count - Forever
Scheduler (Duration) - 900 Seconds [Total 15 Minutes: 5 mins for users ramping up time, 5 mins for your test and 5 mins ramping down time]
To know the details, you can also see this thread on How should I calculate Ramp-up time in Jmeter.
I want to run a JMeter test with a number of concurrent threads with each thread sending a request every 10 seconds.
These are my thread properties.
Number of Threads: 10
Ramp-Up Period: 10
Loop Count: 1
Result: 10 requests divided over 10 seconds, so every second a request and exactly what I want.
Now I want to run this test for 3 times(30 seconds). So I set the Loop Count to 3.
But the result is: 30 requests in 10 seconds. This is strange, because I would expect to run this for 30 seconds and get 1 request per second.
How can I achieve this with JMeter?
My final goal is to run this test for a long period and also increase the Number of Threads.
How to do this with JMeter?
I researched this today and came to this conclusion: The Loop Count setting is a complete misnomer. It doesn't actually loop in any sort of chronological sense, even if your Test Plan has Run Thread Groups consecutively checked. What it does do is multiply your thread group and run all multiples concurrently. Therefore, the Ramp-Up Period is only respected once, and NOT once per "loop" - there is no temporal loop!
An explanation with graphs can be found here: http://pro-programmers.blogspot.com/2009/07/jmeter-max-threads-with-rump-up-and.html
Seems that the most simplest ways to control throughput in your tests is using either standard "out-of-box" Constant Throughput Timer or custom Throughput Shaping Timer from jmeter-plugins collection.
In both the cases structure of the test will be like the following:
Thread Group
Number of Threads = N
Ramp-up Period = N
Loop Count = 1
Constant Throughput Timer
Target Throughput = 60
Calculate Throughput based on = "all active threads in current thread group"
. . .
Loop Controller
Loop Count = M
. . .
HTTP Request
. . .
Here Loop Controller defines number of iterations.
Looks like both the timers are not absolutely precise as well as both are a bit differently configurable:
Here is also a kind of practical example how to vary the throughput.
In my experience with Jmeter if you set
Number of Threads: 10
Ramp-Up Period: 10
Loop Count: 1
you create 10 threads into 10 seconds so you create 1 thread every second.
With loop count of 1 you repeat this once.
But if you increase loop count I think that you don't create new threads but repeat jmeter elements procedure in the Thread Group therefore the time beetween the request isn't 30 seconds but just over 10s.
If you want to create 30 threads within 30 seconds you have to set
Number of Threads: 30
Ramp-Up Period: 30
Loop Count: 1
If you want to repeat 10 threads for 3 times with ramp- up of 10 seconds you should insert a Timert->Constant Timer with thread delay of 10000 ms so you obtain 30 requests in 30 seconds (really you should consider the time of executions of the task)
refer link: http://www.testingjournals.com/5-must-know-features-thread-group-jmeter/
scenario 1 :
number of threads = 20
Ramp-up period =100
loop count=1
Every 5 seconds(100/20) 1 request/thread will hit the server,Execution will start with 1 request at a time
scenario 2 :
number of threads = 20
Ramp-up period =100
loop count=4
Every 5 seconds(100/20) 4 request/thread will hit the server, once the 1st request/thread completes , it will start 2nd loop by executing same HTTP request,Execution lasts until all 20 threads executes all HTTP requests 4 times
My understanding of Ramp-Up is that a value of 0 will fire all threads at the same time (concurrently).
You might be able to achieve what you want by setting the following:
Number of Threads: 10
Ramp-Up Period: 0
Loop Count: N
and then using a Controller to determine when to end each loop.
Yup, the Loop Count parameter is not intuitive. From what I figured out it is actually the number of times the thread/user performs a particular test
So if I understand correctly your intention that you want:
to run N number of concurrent threads/users
each of them sends a request every 10 seconds
you want to run this scenario for around 30 seconds
the configuration should be the following:
Number of Threads: N
Ramp-up Period: 0
Loop Count: 3
And in Constant Throughput Timer (within the Thread Group) you should set Target Throughput (samples per minute)=6, which means request every 10 seconds