You can still use the per-cpu attribute in 7.1.1, so you can define the pool like this:
<core-threads count="10" per-cpu="10"/> <queue-length count="20" per-cpu="20"/> <max-threads count="100"/> </blocking-bounded-queue-thread-pool>
It applies properly but fires a warning:
WARN [org.jboss.as.threads] JBAS012400: The 'per-cpu' attribute is no longer supported. The value [X] of the 'count' attribute is being combined with the value [Y] of the 'per-cpu' attribute and the current processor count  to derive a new value of [Z] for 'count'.
I have also found no way to assign 'per-cpu' via CLI. So it can only be done manually by editing XML.
Can someone explain why this convient feature is sunset?