Why do I see significantly reduced TCP performance in my NicheStack-based Nios II application since upgrading to 8.1?

You may notice lower TCP performance as well as your network application code frequently getting "stuck" in the tcp_sleep()/wakeup() functions. This is due to a problem with NicheStack and the Altera Triple Speed Ethernet MegaCore in version 8.1.

To correct the problem, apply the following patches to version 8.1 of the Altera tools. 

Apply the Triple Speed Ethernet patch by doing the following:

1. Download the  altera_triple_speed_ethernet.zip patch file.
2. Backup the < your Triple Speed Ethernet Megcore install dir >/lib/sopc_builder/triple_speed_ethernet directory.
3. Delete the contents of  original directory specified above.
4. Unzip altera_triple_speed_ethernet.zip into < your TRIPLE_SPEED_INSTALL_DIR >/lib/sopc_builder.

Apply the NicheStack patch by doing the following:

1. Download the altera_iniche_314.zip patch file.
2. Backup the < your Nios II EDS installation dir>/components/altera_iniche directory.
3. Delete the contents of  original directory specified above.
4. Unzip altera_iniche_314.zip into < your Nios II EDS installation dir>/components.