> I've yet to be unable to make a program go "fast enough" regardless of the programming language or runtime it's in. On "fast enough": Performance matters to

> I've yet to be unable to make a program go "fast enough" regardless of the programming language or runtime it's in. On "fast enough": Performance matters to latency and throughput but also resource consumption and thus cost. Ok maybe you haven't worked on anything where measurements like latency and throughput matter. But surely you've worked on something where cost matters? Whether it's paying for additional hardware or VMs or increased memory requirements or more runtime minutes for "serverless" hosting, slower code always costs more to run. If traffic is super low maybe it's the difference between $0.10 and $1.00 so nobody cares. But grow that company and suddenly it's $10K vs. $100K, the CFO is now paying attention. A couple startups ago I redesigned a system so it was able to handle ~50x the user load per server (no special magic, just JVM tuning, DB tuning, removing some of the worst-offender slow code). The ops team had been in the process of ramping up server count and instead they ended up removing 30+% of the servers assigned to it. From a customer perspective it wasn't faster (it actually was faster, but not in a way any customer would've noticed) but higher performance code sure saved us a lot of money.