On 17 October 2016 at 22:08, Robin D. Wilson <rwils...@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:rwils...@gmail.com> rwils...@gmail.com
>
>
>

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