A Duel plugin: every benchmark is judged on the SQL queries, cached queries, transactions and record instantiations Active Record did for it too, whatever the database.

A Duel plugin: benchmarks with threads of their own are judged on how long their threads waited for the GVL too, so a change that adds contention fails even when its CPU time doesn't.

A Duel plugin: each worker gets a memcached server of its own, and every benchmark is judged on the memcached operations, misses and bytes it took too.

A Duel plugin: each worker gets a MySQL server of its own, and every benchmark is judged on the statements it sent, the rows they read and their time too.

A Duel plugin: each worker gets a PostgreSQL server of its own, and every benchmark is judged on the queries it sent, the rows they returned, the buffers they touched and their time too.

A Duel plugin for Rails apps: each version of the app booted like production, with its own bundle and database, and benchmarks of its requests, judged on time, allocations, queries, views and cache use.

A Duel plugin: each worker gets a Redis server of its own, and every benchmark is judged on the Redis CPU time, commands and round trips it took too.

A Duel plugin: every benchmark is judged on the Ruby objects its iterations leave alive after a full garbage collection, so a leak, or a cache that grows with every call, fails.