I've been working on shard balancing for Playwright Test. The idea is to use the new API released in Playwright v1.62 together with historical test durations to balance tests across shards.
I ended up designing a specialized variant of LPT that works well for Playwright test suites. It's now used in WordPress's Gutenberg project, where it cut test runtime from 35 minutes to 23.
The algorithm is called SALT. Here's the detailed write-up if you're interested in job scheduling:
I ended up designing a specialized variant of LPT that works well for Playwright test suites. It's now used in WordPress's Gutenberg project, where it cut test runtime from 35 minutes to 23.
The algorithm is called SALT. Here's the detailed write-up if you're interested in job scheduling:
https://blog.flakiness.io/posts/2026/salt/