JBEAP-2418 has added new configuration option that allows the configuration of the fairness of the semaphore used to manage the connection pools in JCA.

Description of new option should be added at least to Configuration Guide -> 10.9. Reference of Datasource Parameters -> Table 10.9. Datasource Parameters

parameter: pool-fair
type: Non-XA, XA
description: Defines if pool should use be fair

(Description taken from XSD and management model description)

Also the same configuration option is available in resource-adapters subsystem but it seems that there is no documentation for resource adapters yet (JBEAP-2906)

More references:
https://issues.jboss.org/browse/JBEAP-2418
https://issues.jboss.org/browse/JBJCA-1305
https://groups.google.com/forum/#!topic/ironjacamar-developers/2AsxToycwcQ