kern/154428: [xen] xn0 network interface and PF - Massive performance drop

[Mark Felder]

On Mon, Jul 15, 2013, at 23:20, alex at ahhyes.net wrote:
>  
>  Hi Mark,
>  
>  You're certain TSO is enabled for the NIC? ie: Not disabled via 
>  ifconfig or sysctl?
>  

Ok, I just did some further testing again. I left TSO off in production
because I wanted this to match our other servers for now.

With TSO on there are no more speed issues. Before network operations
were slower than dialup, and this is not the case anymore. However,
there is an added bit of latency to all network operations. For example,
a large text output over ssh via "dmesg" with TSO off is instant. With
TSO on there's a 1 second lag before it reaches my terminal.

It appears it's not fully fixed, but it's getting closer. We'll have to
see if the recent XENHVM work in head has made any further progress. I
haven't had time to test it yet.