How to use Gatling to let users run scenario concurrently?

Gatling (Open-Source)
1

Hi,

I’m using Gatling sbt plugin to run some of my test but I found out even though I can bring up users together, but the scenarios can only run by one user at a time.

So I wrote some simple test like this. I set 10 users, I expect to have different users run concurrently so I should see printlns for different numbers. But I can only see one number that means only one user running the scenario.

I’m using sbt plugin version 1.0. gatling core version is 2.0.0

def basicTestAction = {
  exec((session) => {
    withReporting(session) {
2

while(true)???
You’re creating a busy loop that will never release the thread.

3

Hi, Stephane:

Thanks for replying. I meant to make it more clear that it will run one by one.I tried to remove the while loop or give it a limit, but see the same thing, the second user will only run scenario after the first user done.

4

For users spawn at the exact same time (atOnceUsers), first action gets currently executed in the scheduler thread.
Impossible to guess if that’s an issue and if we’d get a speed boost if we were jumping into an event loop here, we’d have to benchmark.
Remember that your usage violates a string Gatling principle: don’t run long computations in our threads.

5

Thanks Stephane.

Do you mean we can’t add event loop in a scenario?

I’m not sure what you mean by “don’t run long computations in our threads”? Could you please explain?

Thanks