Honestly we only hit this traffic in trials, so the details aren't at the top of my mind.

There seem to be some exceptions thrown once the traffic goes above 75r/s, and they slowly degrade performance until 90r/s where we were maxing out our xen slice.

I didn't bother to isolate exactly what was going on because we stopped using thrift at that layer for other reasons (more ruby was introduced, and until Kevin Clark's second rewrite the ruby thrift bindings were pretty painful to use).

I can dredge up the logs if you're interested. I'll contact you outside this venue.