> Most code, i.e. at least 80% of the code in a codebase, will never be a performance hotspot
Yes, and no. That's what makes it hard to write high performance systems, you really need people with solid experience in designing for performance.
Sure, always go for the low hanging fruit which are the hotspots identified by profiling and improve those.
But what often happens after that is that all the code is slow everywhere! So there are no big hotspots, profiling shows nothing egregious. Teams without high performance systems experience might conclude the code is about as good as it can get given the absence of hotspots. Seen this happen often. But there might be 10x or 100x improvements remaining.
Yes, and no. That's what makes it hard to write high performance systems, you really need people with solid experience in designing for performance.
Sure, always go for the low hanging fruit which are the hotspots identified by profiling and improve those.
But what often happens after that is that all the code is slow everywhere! So there are no big hotspots, profiling shows nothing egregious. Teams without high performance systems experience might conclude the code is about as good as it can get given the absence of hotspots. Seen this happen often. But there might be 10x or 100x improvements remaining.