How should I simulate 1000 concurrent users as real?

Question

I need to do a load testing for a web service. It requires at least 1000 concurrent users.

I know some testing tools (e.g JMeter) could simulate a bunch of concurrent users with multiple-threads. But those users are not really concurrent.

If I run the JMeter program in a machine with only 2 CPU cores, there is only 2 concurrent users active in a time, even though there are 1000 multiple threads generated with the testing tool.

Is there any way to create real concurrent users?

Answer 1

From the point of view of the web service, those users are concurrent. A CPU with two cores can easily swap between 1000 threads; most of the time, the thread will be waiting for network I/O, so it's very similar to how it would work if you actually had 1000 cores.

So JMeter should be fine. It's possible that if the test thread has to do a load of CPU-intensive work, then that might bias the results. But usually, the test threads are just waiting for a response.

Answer 2

You can try *nix tool Siege after reading FAQ about concurrent users.