Hi Jesper,
Unfortunately we have no success changing pool / xa-pool.
You are rigth, our problem aren't workers but we can't understand JCA behaviour, so we can't solve the bottleneck.
I would like to explain better the tests we are doing:
* We are using JMeter to stress our API with 50 threads and 30 iterations with 0 seconds "Ramp-up period"
* The tests are performed from a single host located outside the data center against our public ip
* Each thread does 5 HTTP requests
* Each HTTP request makes a few DB calls
* Due to an unknown reason our jboss only uses two "JCA threads" to enqueue all the DB requests of 150 HTTP threads
* This is a fragment of one of the two "JCA threads" (https://gist.github.com/4161046)
Thank you in advance