[pradn]

> Typically, perf isn't a few bad decisions. It's a very large number of independently reasonable decisions that add up to a bad result. If the team loses that discipline for even one moment then it's very very difficult to fix. I wonder if my former team still exists or if they've all been reassigned elsewhere.

This is precisely where the adage "premature optimization is the root of all evil" falls apart. You really do need everyone to care about performance to an obsessive, unreasonable degree to keep the entire, massive system performant. Companies with good engineering leadership understand this. The thousand cuts can come from language, libraries, feature creep, and pure ignorance or carelessness.

[navane]

It's not premature if your crafting an office product in 2025 which sits in a direct line of 30 years of the same word processor.

[pradn]

It's premature in the sense that you need to care about it before you do profiling, which is the usual advice for perf improvements: "you don't know where the hotspots are, so write your code, profile it, and fix the slow bits".