I recently setup an Nginx box to proxy http request to a Wowza http module. When going through nginx the request and response took a long time. I was thinking I just had a slow server but when going directly to Wowza the calls were quick.
So after a bit of thrashing around the internet.. I read some nginx docs.. the secret?
That slowed down my whole request/response stuff. They did mention that when using Comet that this option should be turned off.. well for other http requests that are asynchronous it's a good idea to turn it off as well.
Hope that helps someone doing through the same issues as I was.