Hi Stephane,
I think we should definitely profile this. Can you share a bit more details/reproducer?
In the past we've also relied on the internal performance team to get jfr recordings under proper load in a suitable bench environment. 
Cheers 

On Thursday, October 18, 2018, Stephane Epardaud <stef@epardaud.fr> wrote:

Hi,

I was doing some benchmarks with gatling and came across very strange results where if I have a REST endpoint with normal result types I get 1200 requests per second, but if I return those results inside RxJava's Single (with Single.just()) I get about 250 requests per second, and if I change that with CompletionStage (using CompletableFuture.completedFuture()) I get about 310 requests per second.

Frankly I'm not sure how to go about finding out why we have such a difference, and whether we can mitigate it, but we should definitely try. How do you usually tackle these problems? Any help?

Thanks, cheers.



--

Alessio Soldano

Associate Manager

Red Hat