benchmarking rails app

I've been poking around at some benchmarking to see how my app is performing
(mongrel cluster/pound). Currently, I'm using ab and httperf and collecting
requests/second. I'm not convinced that I'm using realistic loads.

What are others using for the options to these benchmark programs?

Thanks

http://dev.robotcoop.com/Tools/production_log_analyzer/index.html

I attack the problem from the other end. Take actual usage and make that faster. Getting a report of what actions need optimization is a better way to focus your energies.

Creating realistic loads can be hard, so I don't bother trying to simulate it.

Thanks, Eric. I've read your Tools section before and your analysis is
excellent. As an optimization technique, I agree with what you say.

What I'm after right now is a way to understand how much headroom my app
has. I.e., what would happen if we never touched a line of code and then
experienced an order of magnitude more traffic.

I think ab and httperf are somewhat blunt instruments but they can be useful
in understanding some of the response characteristics of different
configurations, no?

Eric Hodel wrote:

Yes, and to get the right traffic mix you can use your logs to get an idea of where that load is likely to go.

I bet you could combine pl_analyze's report (for actions and frequencies) with railsbench's benchmarks.yml to get a realistic answer to your question. You might need to throw in some extra log file analysis to look at params, since some parameters may have wildly different performance characteristics.