[pedrocr]

And what encryption is stunnel using? AES was picked to be fast so it may very well be outperforming whatever stunnel uses.

Can 1200 extra context switches and ~6400 extra interrupts per second use up 100% cpu? In fact you mention that for stunnel most of the CPU was in userspace and not the kernel which would indicate time spent actually using the CPU instead of doing context-switches and interrupts, which I assume top would show as "sys".

I also find the extra interrupts strange. I wonder if vCider is sending bigger packets and what caching/latency implications that might have.

[aidenn0]

Also, I had a bitch of a time getting performance out of stunnel, it seemed to ignore hardware acceleration units that openssl was happy to use.

[jbrendel]

vCider does not use larger packets. It can't, since they still have to be routed over the same public Internet.

stunnel tries to compress traffic as well, which works if you send a lot of stuff that isn't already compressed. But most of what's sent these days (multi-media?) already is encrypted, so this will be a wasted effort.