benchmarking koji

[Ken Dreyer]

If we had a "koji benchmark" tool, what would you like it to do?

I've written an Ansible playbook that automatically sets up Koji
according to our documentation, and I want to exercise the hub to see
how it performs. We can use a benchmark tool to understand changes
that could impact performance. As one example, we probably want to
compare CentOS 7, 8, and Fedora.

What scalability problems have you encountered with Koji in the wild?

I'm thinking of things like:
- Tagging thousands of builds quickly
- Contention on the sessions table
- Maintaining thousands of builders
- Ensuring kojira runs in a timely manner

When we have test data, even if the benchmarks are fairly synthetic,
it's easier to see the impact of code changes before we ship.

(As an aside, I started writing a really simple "echo" and "login"
benchmark tool using the txkoji library, but I found that Twisted's
built-in XML-RPC client only supports HTTP/1.0, so no keepalives!)

- Ken