The Cost of thread_local
<p>Now that C++ is adding thread_local storage as a language feature, I'm wondering a few things:
1) What is the cost of thead_local likely to be?
   a) In memory?
   b) For read and write operations?
2) Associated with that: How do Operating Systems usually implement this? It would seem like anything declared thread_local would have to be given thread-specific storage space for each thread created.</p>
