cmd/compile: provide default PGO profiles that cover the runtime

[Jorropo]

Given no PGO coverage should have minimal impact and there seems to be limited ways to use the runtime codepaths.
It might be worth collecting average profiles for some go programs, filter for the runtime (or maybe std) and apply it if no profile at all were provided. This wouldn't make your code faster, but might for std and runtime.

Both seems benchmarkable claims, then we could discuss the process costs to collecting and maintaining such profiles.

similar to #70291 this idea came up during a brief PGO discussion at the Go contributor summit at golab.io

[gabyhelp]

Related Issues

• cmd/compile: profile-guided optimization #55022 (closed)
• proposal: runtime: optionally dump PGO profile at the program exit #62444
• cmd/compile: design and implementation of Profile-Guided Optimization (PGO) #55025 (closed)
• cmd/compile: consider giving a warning or an error if a PGO profile looks mismatched #70291
• cmd/pgopack: cache packed pgo profile during build #62400 (closed)

Related Documentation

• Profile-guided optimization preview > Example > Using the profile

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}