Any well written server application eventually comes down to how fast can you copy the data.  This avoids a copy so it can double performance.<p>As for headers&#x2F;trailers, it&#x27;s a file descriptor, nothing prevents you from writing to it before or after the sendfile() call.<p>Simple primitives are fine but this is faster.  Unless you are going to do the page flipping tricks that Irix did, you can&#x27;t approach this speed (and Irix tricks aren&#x27;t as fast as this, better than the bcopy() but not as fast as this).