title: Improve Boost Property Tree performance
body: <p>I coded a simple JSON wrapper on top of boost property trees (available at <a href="https://github.com/mariolpantunes/JSONObject" rel="nofollow noreferrer">github</a>).</p>
  <p>The focus of the library is to mimic interface of org.json (java JSON library). However it is taking 2 seconds to insert a string array of 1000000 (1M) elements.</p>
  <p>For comparison the same code in java, using org.json, takes only 0.071 seconds.
  One interesting thing that I saw was that the java code used all my cores while my c++ code only uses one core.</p>
  <p>Is there a way to optimize this?
  Does boost have a multi-thread property tree?</p>