To concur it's "latency critical", not "performance critical", people often confuse those two - optimize it all, but especially the chained critical path latency!
If I have the same number of CPU cores and they all can do their work in half the time they can double the number of requests now
Heck, even latency alone you can just reduce the standard deviation and get smoother flows. Little's law is a great callout here too, one of my favorite computer science principles.