title: ParVector map is not running in parallel
body: <p>I have a bit of code like:</p>
  
  <pre><code>val data = List(obj1, obj2, obj3, obj4, ...).par.map { ... }
  </code></pre>
  
  <p>and the ParVector is roughly 12 elements large. I noticed that all of my work is being done in the main thread so I traced down the stacktrace and found that in the following line (in the link below), ifParallel is false (from CanBuildFrom). Any hints as to why it's false, and what I can do to help it?</p>
  
  <p><a href="https://github.com/paulp/scala-full/blob/2.9.0.1/src/library/scala/collection/parallel/ParIterableLike.scala#L504" rel="nofollow">https://github.com/paulp/scala-full/blob/2.9.0.1/src/library/scala/collection/parallel/ParIterableLike.scala#L504</a></p>