Concurrent static file handling in Tornado is blocking?

Question

I have a webserver which among other things serves static files. From this http://tools.pingdom.com report, it seems something is blocking when serving several files at the same time to the same client?

The wait-time increases for each image:

Report: http://tools.pingdom.com/fpt/dgrKAX/http://arkgis.org/DIQAB7

Why is this? The files are served with the default tornado.web.StaticFileHandler class, but this is not the behaviour that I expected! We have a need for speed!

What can I do to fix this?

EDIT:

I've now set up a nginx front-end — but I actually get the same increasing connect times in pingdom.com. Am I reading the report wrong? Is this due to something client-side? Or is my nginx configured wrong?

Report with nginx front-end:

Answer 1

Use nginx.

File access in Python is blocking, so the Tornado IOLoop is going to be blocked while reading from disk.