I was just wondering how many concurrent requests you have managed to generate using this module.

I'm not sure, but each 'thread' of our test script sleeps between requests to simulate the time taken to fill in each form. We have the load generation scripts running on a number of different client machines.

I am assuming that calling lwprequest directly will allow more parallel requests to be generated than the overhead of using the perl interfaces like this.

Um no, lwp-request is just a Perl script that uses the LWP module. It's all Perl.

What do you think is the best way to generate the most parallel requests?

We're not really interested in raw 'requests per second' numbers since we want to know how many simultaneous user sessions the servers can handle. What constitutes a 'user session' for your app would be quite different to ours.

The ApacheBench (ab) tool bundled with Apache might be one way to generate many parallel requests. The mod_perl performance tuning guide has other suggestions.