websocket-server seems to be (very) slow

After multiple tests and iterations, here is the average behavior with tor1.bamsoftware.com with the following configuration:

Browser (2 Mbps) --> 600kbps --> tor1 300 kbps --> Tor 2 Mbps --> ORDB (400/500 kbps) --> Tor 2 Mbps --> 2 Mbps --> Browser (2Mbps) (real: 300kbps)

Where ORDB is for now a small limited server relaying messages. (X bps)=internal processing time based on iterations of 500B blocks.

It appears that tor1 can not handle more than 250/300 kbps, it can be seen too monitoring the WebSockets bufferedAmount on browser side.

Apparently it's not a bandwidth issue or an OR issue since I have tested tor1 as a normal OR (ie w/o websockets).

I have tested too replacing tor1 by a router supporting websockets and the limitation disappears.

So I am suspecting that websocket-server module is abnormally slow.