Breakpad/Design/Loadtesting

Load Testing Plan

Below is a list of items we plan on doing for load testing. In general, the best way we've had to test load has been to:

• Get an estimate of our concurrent load
• Get log samples
• Use oremj's log replay script to replay logs and check results

The main reason why we use log replay is that it's a better way to imitate actual load than AB (AB tests the cache and is only one page).

General Approach

Since we don't fully know what our required req/s capabilities are with what concurrency, here are some of the preliminary things we should find with our first run:

• where the current bottleneck is
• how we can improve it
• where other weak points in performance are

It would also be useful to us xdebug or equivalent to profile the reporter and collector web applications, but I have not done that in Python (only PHP). It's useful for finding expensive operations -- taking the traces and throwing them into kcachegrind has proven useful in the past for our PHP applications.

Stuff We Need to Start Testing

• Need collector logs and example post data to send to collector.
• Need reporter logs to replay.

Processor

The processor will be the tricky part, but it's more scalable than the other pieces since we control the rate. It would be useful to build in some rate or time tracking pieces to the processor so we understand how fast it can process reports.