my mod_wsgi/django app has ~2s response time with or without memcached in-memory caching.
response is the same 2s with or without DNS resolution (i.e. with direct IP request)
for comparison, a simulaneously running mediawiki php process running with APC has sub-second response.
the machine is not out of memory and I can tell that memcached uses up some space.
I've seen the same django app run twice faster on some other machine (of which I unfortunately know little details, but it seems to be running on webfactional) my machine is dedicated host.
here is my apache directive to run the app
<VirtualHost ...:80>
ServerAdmin ...
DocumentRoot ...
ServerName ..
WSGIScriptAlias / /../wsgi-script.wsgi
CustomLog ... common
ErrorLog /.../error_log
DirectoryIndex index.html
</VirtualHost>
EDIT ok found the source of the problem - wsgi was serving static files and that's what drained the performance. Some Alias-type directives for static content fix the issue.
Are you using the built-in development server? Last time I checked that wasn't really meant for production. Consider using Apache with mod_wsgi if that is the case. Here are the instructions.