Reality is sometimes a bit different from theory here. Let&#x27;s say you want to send a small amount of data (1k) from a file to network, some header before it and some trailer behind it. With sendfile you would do three system calls, two normal writes and a sendfile. Without it you would read the file, copy the content, the header and the trailer into a single buffer and issue a single write syscall with it (of course you have the read call before). Due to the lower number of write calls this <i></i>could<i></i> be faster then sendfile, as copying a small amount of data might yield a lower overhead then multiple write requests. Of course that situation will change depending on the amount of data - so I think sendfile is one possible optimization that should be benchmarked for the particular application before using it everywhere.