Hi,

	The following two patches, that I cooked today and haven't
properly benchmarked, implements a new socket syscall, recvmmsg, that
stands for receive multiple messages, in one call.

	I implemented the attached program as a test case and to show
it in action, and lightly tested it using two clients (netcat) sending
big files from a machine with a 100 mbit/s NIC and another with a 1
Gbit/s NIC to a server with the patched kernel, output:

$ ./recvmmsg 5001 128
nr_datagrams received: 19
    4352 bytes received from doppio.ghostprotocols.net in 17 datagrams
    256 bytes received from filo.ghostprotocols.net in 1 datagrams
    256 bytes received from doppio.ghostprotocols.net in 1 datagrams
nr_datagrams received: 14
    2816 bytes received from doppio.ghostprotocols.net in 11 datagrams
    256 bytes received from filo.ghostprotocols.net in 1 datagrams
    512 bytes received from doppio.ghostprotocols.net in 2 datagrams
nr_datagrams received: 19
    2304 bytes received from doppio.ghostprotocols.net in 9 datagrams
    256 bytes received from filo.ghostprotocols.net in 1 datagrams
    2304 bytes received from doppio.ghostprotocols.net in 9 datagrams
nr_datagrams received: 14
    2816 bytes received from doppio.ghostprotocols.net in 11 datagrams
    256 bytes received from filo.ghostprotocols.net in 1 datagrams
    512 bytes received from doppio.ghostprotocols.net in 2 datagrams
nr_datagrams received: 19
    4608 bytes received from doppio.ghostprotocols.net in 18 datagrams
    256 bytes received from filo.ghostprotocols.net in 1 datagrams

filo is the machine with a 100 mbit/s NIC, obviously :-)

	There are some things I probably will change, like perhaps
pushing it deeper from socket to sock level, but I'd like to hear about
the general feeling about at least the userspace interface.

Best Regards,

- Arnaldo