title: Are there any benefits to GC performance from immutable objects (functional languages)?
body: <p>It is rising popularity of functional languages due to effective way to utilize multi-core CPUs (because immutability invariant provide some guarantees that allow some optimization) but are there any benefits to garbage-collector performance from immutability?</p>
  
  <p><strong>UPDATE</strong> During my search I found only  one argument - possibility to avoid <em>write barrier</em> in GC algorithm (on sweep stage only, when GC at compat/defragmentation stage we still need <em>write barrier</em>, but that happen not often).</p>