io_lib and unicode post processing?

[Musumeci, Antonio S]

I've got a webmachine/mochiweb setup and it seems much slower/higher CPU than I expected. I'm creating JSON for 10k records using jsonerl and sending on to webmachine. After the serializing of the data the CPU is still pegged and I see in etop io_lib and unicode being called. Does anyone know why those would be called? It takes several seconds.