multithreading - Scala Parallel Collections: How to know and configure the number of threads -

i using scala parallel collections.

val largelist = list.par.map(x => largecomputation(x)).tolist 

it blazing fast, have feeling may run out-of-memory issues if run may "largecomputation" in parallel.

therefore when testing, know how many threads parallel collection using , if-need-be, how can configure number of threads parallel collections.

here piece of scaladoc explain how change task support , wrap inside forkjoinpool. when instantiate forkjoinpool pass parameter desired parallelism level:

here way change task support of parallel collection:  import scala.collection.parallel._ val pc = mutable.pararray(1, 2, 3) pc.tasksupport = new forkjointasksupport(new scala.concurrent.forkjoin.forkjoinpool(2)) 

so case

val largelist = list.par largerlist.tasksupport = new forkjointasksupport(   new scala.concurrent.forkjoin.forkjoinpool(x) ) largerlist.map(x => largecomputation(x)).tolist