=== Week 0: TCP performance test and tunning ===
=== May 13th to May 23th ===
  * Implement TCP receive queue
  * Implement TCP SACK [RFC 2018]
  * Implement TCP Window Scale [RFC 1323]

The test results can be found at these notes:
  * [[soc:2010:cooldavid:notes:tcpoorxtest|TCP out-of-order receive dstat test logs]]
  * [[soc:2010:cooldavid:notes:bkobench|Benchmarks for downloading image from boot.kernel.org]]

== Found TCP FIN ACK number issue ==
Upper layer protocols stop the TCP xfer by calling tcp_xfer_close().

If the call path is:
     tcp_rx()->tcp_rx_data()->...Upper layer...->tcp_xfer_close().

     Which is at lease happened in HTTP while received expected
     length of data.

Sending FIN in tcp_xfer_close() in this case, will cause error ACK
number, since the ACK number have not updated by that time.
Later trying to send a correct one in tcp_rx() will fail too, due
to the TCP state already changed.

This patch let the TCP stack send FIN in normal tcp_rx() flow if the
packet contains the last data of the session.

  * [[http://git.etherboot.org/?p=people/cooldavid/gpxe.git;a=commitdiff;h=d3661b67b1fa15c17b855b7e5cad47c1391835be|The git commit of my fix]]
  * [[https://git.ipxe.org/ipxe.git/commitdiff/9ff822969300a086ad13036c019aa981336017ed|mcb30's patch]]