Earlier quoted context omitted.
Your “thoughts” are applying his solution to the wrong problem. “Start small and stay small” I’m not sure what that even means. Are you saying every service has to grow to some size or required amount of compute? LOL The 100ms extra time is nothing. I mean - are you trying to solve at Google or Amazon scale? I run simple Lambdas that read from some SNS topics, apply some transforms and add metadata to the message, an…
100ms of unneeded latency IS NOT nothing (except for some limited use cases). Anything user facing shouldn't be slower than it needs to be.
Let’s say I’m processing messages off a queue. P90 @ 50ms vs p90 at 100ms doesn’t necessarily make a difference. What are my downstream dependencies? What difference does it make to them?
At the end of the day, value is what you care about - not necessarily chasing a metric because lower is absolutely better. What’s the cost of another x milliseconds of latency considering other trade offs (on going operational burden, extensibility, simplicity, scalability, ease of support etc etc).
If 50 ms latency means I can have a solution that can auto scale to massive spikes in traffic due to seasonality or time of day vs a reduction of that latency but I have to spend time capacity planning hardware and potentially holding extra capacity “just in case”, then again, optimizing for a single metric is pointless.