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From "Robin D. Wilson" <rwils...@gmail.com>
Subject RE: How would you go about creating a new Thread Group type?
Date Mon, 17 Oct 2016 21:56:53 GMT
The idea with the CSV data set works perfectly. Seems like a good workaround... But I'd still
like to experiment with building my own Thread Group widget...

--
Robin D. Wilson
Voice: 512-426-3929
rwilson2@gmail.com

-----Original Message-----
From: sebb [mailto:sebbaz@gmail.com] 
Sent: Monday, October 17, 2016 4:23 PM
To: JMeter Users List <user@jmeter.apache.org>
Subject: Re: How would you go about creating a new Thread Group type?

On 17 October 2016 at 22:08, Robin D. Wilson <rwilson2@gmail.com> wrote:
> Just throwing this out there - to see if anyone wants to lead a 
> code-level newbie down the right path. I've been using JMeter for
> 8-9 years now, and really like it. But one thing that bugs me is the 
> way the Thread Group works. Specifically, the idea of the "loops" bothers me.
>
>
>
> Consider this scenario:
>
>
>
> 1)     100 "users" (e.g., threads)
>
> 2)     10 loops
>
> 3)     Test has 10 HTTP Requests in it
>
>
>
> By this logic, you should end up with 100 (users) X 10 loops X 10 HTTP Requests = 10,000
requests.
>
>
>
> And you do.
>
>
>
> BUT, what you actually get when you run the test isn't as clear as you 
> think. It is basically 100 threads, each running 10 times, and each thread loop running
10 HTTP requests in sequence.
>
>
>
> Here's the problem, if thread 1 completes its 10 loops in 100 seconds, 
> but threads 2-100 take 200 seconds to complete their 10 loops. The 
> load will be reduced to only 99 simultaneous threads (users) for the 
> last 100 seconds of the test run. That's not a 'huge' deal, but it can 
> affect the perception of the test if you look at it more like threads 
> 1-50 finish in 100 seconds, and threads 51-100 take an extra 100 
> seconds after that to complete. Then only half of your test cycle was 
> at the required 'max' load you wanted to create, while the other half 
> was at 50% of the required load. (It is reasonably possible that I'm 
> just misinterpreting how it actually works, but it appears to work 
> like this from my experience since I can see threads continuing to 
> process after some threads appear to stop - and it lasts longer than 
> it takes to get through the entire cycle - sometimes for several 
> minutes at the end of a test run.)
>
>
>
> I'd like to create a new Thread Group that doesn't assign the thread 
> to the loop until it starts again at the top of the cycle. So if 
> thread-1 finishes really fast, and there are still loops to run - it 
> just picks up another loop and runs it. I would always want to 
> maintain at least 100 threads executing, so long as there were loops left to run. So
basically, you multiply the number of loops by the number of threads (1000 in my example),
and your 100 threads always restart until there are no loops left to run. Then the longest
period you have where you aren't fully loading the servers is just the last loop for every
thread.
>

You can probably do this by using a CSV Data set with 10000 entries.
Each thread picks the next entry (does not matter what it is) and runs the test samples.
When all the entries have been used up, stop the test.

But the normal way to do this is to make sure that the test runs for long enough that startup
and shutdown variations don't affect the results.

>
> BUT, I am not 100% sure where I would start in the source code. I have 
> programmed before (a long time ago), but if someone could point me in 
> the right direction (like, which source files would need to be modified, and how would
I register my new Thread Group as a different option), I think I could figure it out pretty
quickly.
>
>
>
> --
>
> Robin D. Wilson
>
>  <mailto:rwilson2@gmail.com> rwilson2@gmail.com
>
>
>

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