Hey :) I thought of a thing that I don't have time to implement right now: perf jitmap support in Guile.
Basically, the "perf" Linux tool is a widely-available instruction-level and microarchitectural profiler. It's great: you run "perf record guile foo.scm", and then you run "perf report", and you get instruction-level info on the profile. You can grab call graphs, see performance counters, all kinds of things. Good stuff. With run-time code generation though, perf needs some help from the program generating code. The most basic step is what's known as "perf maps", placed in /tmp/perf-$PID.map. These are super-basic and just identify code ranges with functions. I just pushed a patch doing this. The more useful thing is what's known as "jitmaps". See https://lwn.net/Articles/633846/, and https://chromium.googlesource.com/v8/v8/+/refs/heads/master/src/diagnostics/perf-jit.cc. It's totally underdocumented, but it actually saves the JIT code to a file, which is needed to have instruction-level profiling. It also adds support for unwinding frames and source info. Anyway if anyone wants to take this task in the next few weeks, LMK :) Andy
