Qt Threads vs Native Threads performance

[StackOverflow]

Hi there

I have to develop a multithread application, and i want to use Qt since that application has to be used in Linux and FreeBSD. I have to implement a file server.
Qt gives me a multiplataform solution.
But what about performance ? Could be much less than using native threads ?
Thanks

[Zlatomir]

Note: Qt's threading classes are implemented with native threading APIs; e.g., Win32 and pthreads.

Quoted from here

So with one level of abstraction over the native threads you should not "see" a difference in performance. (You can always test and see exactly how much performance you gain if you use native threads)