Re: [Gatling List] Users per second and response times

[Stéphane LANDELLE]

Hi, 

Am I correct in saying that a user waits to be be notified of a response through a future?

Basically :)

 

So, if I have 50 users per second in the simulation, but the total response times for that user are > 1 second, will I be unable then to reach 50 users per second in the test run? 

That's an open model, user arrival rate is not related to the response time. New users keep on arriving at a 50/s rate, period.

[Stéphane LANDELLE]

Your question was about user arrival rate, not rps. :)

If scenarios contains more than one request (ie each user performs more than one request), of course global rps will drop if response time increases:

• 1s response time + 5s think time + 1s response time = 2/7 rps = 0.29
• 5s response time + 5s think time + 5s response time = 2/15 rps = 0.13

Stéphane Landelle

Lead developer

slan...@gatling.io

On Tue, Mar 24, 2015 at 6:20 PM, empty account <do.not....@gmail.com> wrote:

Thanks for the reply Stephane, but why then would I get a significant drop in requests when the response times increase?

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[Stéphane LANDELLE]

Each individual virtual user behaves like a physical person: you have to wait for a response (like a web page) before being able to perform the next action (like clicking on a link in this page).

But virtual users are NOT coordinated altogether.

Stéphane Landelle

Lead developer

slan...@gatling.io

On Tue, Mar 24, 2015 at 8:41 PM, empty account <do.not....@gmail.com> wrote:

In fact, why does the request per second (RPS) include the response time? Are we then not calculating the throughput? If the RPS includes the response time, then wouldn't the RPS always be less than the response time per second?

Aidy

On 24 March 2015 at 18:10, empty account <do.not....@gmail.com> wrote:

Got it. Took me a while. thanks.

[Stéphane LANDELLE]

Requests per second or responses per second?

How high do you load? What does Gatling GC activity look like?

Stéphane Landelle

Lead developer

slan...@gatling.io

On Tue, Mar 24, 2015 at 9:46 PM, empty account <do.not....@gmail.com> wrote:

OK. The problem I have then is that I have one request per user, but still the requests per second falls dramatically when max times significantly increase. I am not sure why this would be the case. 

[empty account]

I ran jstat and didn't see any unusual gc activity when the requests dropped off (at around 525 RPS). I duplicated the request in the scenario and ran my desired load at 800 RPS without an issue.  Not entirely sure why this would be the case. 

[Stéphane LANDELLE]

> I duplicated the request in the scenario and ran my desired load at 800 RPS without an issue.

Sorry, I don't get what you mean. You mean that you ran the simulation a second time?

Stéphane Landelle

Lead developer

slan...@gatling.io

[Stéphane LANDELLE]

Would need a reproducer.

Stéphane Landelle

Lead developer

slan...@gatling.io

On Wed, Mar 25, 2015 at 5:28 PM, empty account <do.not....@gmail.com> wrote:

Hi Stephane, 

Sorry, I have not explained myself properly. 

I have a scenario with one request. When I run the test the requests drop off at around 525 RPS (when my ramp up is to 800)

I added the same request in the scenario and I am now able to reach 800 RPS. 

Aidy

[CyberNinja]

>> If scenarios contains more than one request (ie each user performs more than one request), of course global rps will drop if response time increases:

How can I keep the global RPS consistent?