First off, thanks for the awesome tool and phenomenal documentation! I
wish more projects had docs even half as good.

I've been hitting what seem to be pretty restrictive performance
limits with django, mod_wsgi, and apache. This may be an apache
problem, but I'm running out of idea of what to do and who to ask, so
I thought I'd ask here.

When I run load testing benchmarks, the average response time scales
pretty linearly with the number of concurrent requests I'm making. I'd
expect to see increasing delays if I was making more concurrent
requests than the number of apache workers, apache max clients, or
mod_wsgi daemon threads, but it starts happening with 2 concurrent
requests.

Here's a graph showing the avg response time for a static file, plain
wsgi hello world app, and django hello world page-
https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AurdDQB5QBe7dGFncnlUNkdKMVJ4NnYtRjhjaGFIeFE&output=html.
Obviously, if apache is adding some amount of delay for each
additional concurrent request, mod_wsgi and django can't go any faster
than that, but it looks like each layer in the stack is adding some
delay of its own that gets worse with each additional concurrent
request.

These times are small enough that it's not a big deal if I have 40
concurrent requests, but the problem is much worse with my full app.
I've got a page that does a whole bunch of work. When I make one
request at a time the response time is on the order of 100 ms. With 10
concurrent requests, the avg response time is well over a second. All
the work that the page is doing is going to slow things down, but
there's still this linear scaling of response time and I wonder if
it's being caused by whatever is causing the linear performance with
the hello world page.

Any thoughts or what might be causing this or how to troubleshoot
further? I asked on server fault about the static file part of it and
haven't really gotten anywhere-
http://serverfault.com/questions/344788/why-is-static-page-response-time-going-up-with-increased-concurrent-requests

Thanks so much,
Dan

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