> As for your "blocksize = filesize" argument I changed my opinion:
> despite being less CPU consuming we might incur into problems if
> that number is too big.  'count' parameter on Linux, for example, is
> expected to be an unsigned int.
> Other plarforms will also use different data types so we better stick
> with a fixed blocksize value (currently 8192).

If you really think a blocksize is necessary, you could choose a much
larger one for sendfile() (such as 16 MB). Then the overhead of system
calls would be much smaller.